Gas phase polymerization process

ABSTRACT

A process for producing polymer in a gas phase reactor by introducing a stream of monomer and gas into a polymerization zone while providing at least one liquid component in the polymerization zone.

This application is a continuation-in-part of prior U.S. applicationSer. No. 09/179,218 filed Oct. 27, 1998, now U.S. Pat. No. 6,096,840,which was a continuation-in-part of U.S. application Ser. No.08/510,375, filed Aug. 2, 1995, now U.S. Pat. No. 5,834,571, which was acontinuation-in-part of U.S. application Ser. No. 08/284,797 filed Aug.2, 1994, now U.S. Pat. No. 5,453,471.

FIELD OF THE INVENTION

This invention relates to a new gas phase polymerization process usingliquid in an otherwise gas-phase process.

BACKGROUND OF THE INVENTION

The discovery of gas-phase fluidized bed and stirred reactor processesfor the production of polymers, especially polyolefin polymers, made itpossible to produce a wide variety of new polymers with highly desirableand improved properties. These gas-phase processes, especially the gasfluidized bed process, provided a means for producing polymers with adrastic reduction in capital investment expense and dramatic savings inenergy usage and operating costs as compared to other then conventionalpolymerization processes.

In a conventional gas fluidized bed process a gaseous stream containingone or more monomers is passed into a fluidized bed reactor containing abed of growing polymer particles in a polymerization zone, whilecontinuously or intermittently introducing a polymerization catalystinto the polymerization zone. The desired polymer product is withdrawnfrom the polymerization zone, degassed, stabilized and packaged forshipment, all by well known techniques. Most polymerization reactions,e.g., polymerization of olefins, are exothermic, and substantial heat isgenerated in the polymerization zone which must be removed to preventthe polymer particles from overheating and fusing together. This isaccomplished by continuously removing unreacted hot gases from thepolymerization zone and replacing them with cooler gases. The hot gasesremoved from the polymerization zone are compressed, cooled in a heatexchanger, supplemented by additional amounts of monomer to replacemonomer polymerized and removed from the reaction zone and then recycledinto the bottom of the reactor. Cooling of the recycled gases isaccomplished in one or more heat exchanger stages. The sequence ofcompression and cooling is a matter of design choice but it is usuallypreferable to provide for compression of the hot gases prior to cooling.The rate of gas flow into and through the reactor is maintained at alevel such that the bed of polymer particles is maintained in afluidized condition. The production of polymer in a stirred bed reactoris very similar, differing primarily in the use of mechanical stirringmeans to assist an upwardly flowing stream of gases in maintaining thepolymer bed in a fluidized condition.

Conventional gas phase fluidized bed resin production is very well knownin the art as shown, for example, by the disclosures appearing in U.S.Pat. Nos. 4,379,759; 4,383,096 and 4,876,320, which are incorporatedherein by reference.

The production of polymeric substances in gas phase stirred reactors isalso well known in the art as exemplified by the process and equipmentdescriptions appearing in U.S. Pat. No. 3,256,263.

For many years it was erroneously believed that to allow liquid of anykind to enter into the polymerization region of a gas phase reactorwould inevitably lead to agglomeration of resin particles, formation oflarge polymer chunks and ultimately complete reactor shut-down. Thisconcern caused gas phase polymer producers to carefully avoid coolingthe recycle gas stream entering the reactor to a temperature below thecondensation temperature of any of the monomers employed in thepolymerization reaction.

Comonomers such as hexene-1, 4-methyl pentene and octene-1, areparticularly valuable for producing ethylene copolymers. These higheralpha olefins have relatively high condensation temperatures. Due to theapprehension that liquid monomers in the polymerization zone would leadto agglomeration, chunking and ultimately shut down the reactor,production rates which depend upon the rate at which heat is removedfrom the polymerization zone, were severely constrained by the perceivedneed to maintain the temperature of the cycle gas stream entering thereactor at temperature safely above the condensation temperature of thehighest boiling monomer present in the cycle gas stream.

Even in the case of polymerization reactions conducted in fluidized,stirred reactors, care was exercised to maintain the resin bedtemperature above the condensation temperature of the recycle gas streamcomponents.

To maximize heat removal it was not unusual to spray or inject liquidinto or onto the polymer bed where it would immediately flash into agaseous state by exposure to the hotter recycle gas stream. A limitedamount of additional cooling was achieved by this technique by theJoule-Thompson effect but without ever cooling the recycle gas stream toa level where condensation might occur. This approach typically involvedthe laborious and energy wasting approach of separately cooling aportion of the cycle gas stream to obtain liquid monomer for storage andsubsequent separate introduction into or onto the polymerization bed.Examples of this procedure are found in U.S. Pat. Nos. 3,254,070;3,300,457; 3,652,627 and 4,012,573.

It was discovered later, contrary to the long held belief that thepresence of liquid in the cycle gas stream would lead to agglomerationand reactor shut-down, that it is indeed possible to cool the entirecycle gas stream to a temperature where condensation of significantamounts of monomer would occur without the expected dire results whenthese liquids were introduced into the reactor substantially intemperature equilibrium with the recycle gas stream. Cooling the entirecycle gas stream produces a two-phase gas-liquid mixture in temperatureequilibrium with each other so that the liquid contained in the gasstream does not immediately flash into vapor. Instead, a substantiallygreater amount of cooling than previously thought possible takes placebecause the total mass of both gas and liquid enters the polymerizationzone at a temperature substantially lower than the polymerization zone.This process led to substantial improvements in the yield of polymersproduced in the gas phase, especially where comonomers which cancondense at the temperatures of the polymerization zone, are used. Thisprocedure, commonly referred to as “condensing mode” operation, isdescribed in detail in U.S. Pat. Nos.4,543,399 and 4,688,790 which areincorporated by reference.

In condensing mode operation, the two-phase gasliquid mixture enteringthe polymerization zone is heated quite rapidly and is completelyvaporized within very short distance after entry into the polymerizationzone. Even in the largest commercial reactors, soon after entry into thepolymerization zone all liquid has been vaporized and the temperature ofthe then totally gaseous cycle gas stream raised, by the exothermicnature of the polymerization reaction. The ability to operate a gasphase reactor in condensing mode was believed possible due to the rapidheating of the two-phase gas liquid stream entering the reactor coupledwith efficient constant back mixing of the fluidized bed leaving noliquid present in the polymer bed more than a short distance above theentry level of the two-phase gasliquid recycle stream.

Commercial polymerization operations have used for years relatively highlevels of condensate in the recycle streams, in many instances in excessof 20 weight percent liquid was contained in the recycle stream butalways above, the dew point for components in the polymerization zone toassure quick volatilization of the liquid.

While fluidized bed polymerization processes have found particularadvantage in the manufacture of polyolefins, the types of polymerizationcatalysts have been limited to those which are operable in the gasphase. Consequently, catalysts that exhibit activity in solution phasereactions and those which operate by ionic or free radical mechanismsare typically not suitable for in gas phase polymerization processes.

SUMMARY OF THE INVENTION

We have now found that in gas or vapor phase polymerization processes(the terms are used interchangeably in the art and in thisspecification), by providing at least one component in thepolymerization zone, which component is capable of being liquid underthe temperature, pressure and its concentration in the polymerizationzone (herein referred to as “Liquid Component”), the polymerizationprocess is enhanced. The concentration of the Liquid Component ismaintained in the process of this invention, below that which undulyadversely affects the ability of the polymer bed to be fluidized andremain in the gaseous or vapor phase.

While not limited to any particular type or kind of polymerizationreaction, this invention is particularly well suited to olefinpolymerization reactions involving homopolymerization andcopolymerization of relatively high boiling monomers.

Examples of higher boiling monomers capable of undergoing olefinicpolymerization reactions are the following:

A. higher molecular weight alpha olefins such as decene-1, dodecene-1etc. and styrene.

B. dienes such as hexadiene, vinyl cyclohexene, dicyclopentadiene,butadiene, isobutylene, isoprene, ethylidene norbornene and the like.

C. polar vinyl monomers such as acrylonitrile, maleic acid esters, vinylacetate, acrylate esters, methacrylate esters, vinyl trialkyl silanesand the like.

These higher boiling monomers can be homopolymerized in accordance withthis invention with the use of an inert gas as the gaseous component ofthe two phase gas-liquid mixture cycled through the reactor. Suitableinert materials for this purpose include nitrogen and saturatedhydrocarbons which remain gaseous at a temperature below the temperatureselected to be maintained in the polymerization zone.

The higher boiling monomers can also be copolymerized with one or morelower boiling monomers such as ethylene, propylene and butene, as wellas with other higher boiling monomers such as those mentioned above, theonly requirement being that there be a sufficient difference in thecondensation temperatures of the higher boiling monomer and at least onelower boiling monomer or inert substance as will allow enough gas to bepresent in the cycle gas stream to permit practical, steady state,continuous operation.

In accordance with our invention the higher boiling monomers can bedirectly introduced into the polymerization zone or carried into thepolymerization zone as with the recycle gas stream.

Enhancements that may be achieved in accordance with this inventioninclude one or more of the following: increases in production rate;improved catalyst productivity (particularly for catalysts that tend todeactivate, or exhibit accelerated rates of deactivation, withincreasing temperature) leading to reduced catalyst residues and lowercatalyst costs; reduction in localized regions of higher temperature(“hot spots”) in the polymerization bed, facilitated operation controlparticularly for maintenance of desired temperatures; practical abilityto operate at temperatures closer to the fusion temperature of thepolymer particles being produced since the Liquid Component providesbetter heat control; improved operation through reduction in thegeneration of static; improved ability to make sticky polymers;reduction in the risk of fusion of polymer upon emergency shut-down ofthe reactor; improved ability to operate at higher bed density ratios;improved efficiency in conversion of monomers to polymers through thereduction of fines exiting the polymerization zone and reduced foulingwithin the reaction system of the type caused by the presence of fines;enhanced ability to control comonomer incorporation in a copolymer;ability to use catalysts that otherwise would not be attractive forfluid bed polymerization processes such as ionic and free radicalcatalysts; enhancements in the use of solution catalysts for gas phasepolymerizations; an ability to enhance the polymer product throughmorphology control and incorporation of other polymers and additives; anability to achieve more uniform product properties via more uniformtemperatures between different particles and within polymer particlesduring polymerization, through morphology control, and throughincorporation of other polymers and additives.

The processes of this invention involve the production of polymer by thereaction, usually exothermic, of one or more monomers in a fluidized bedreaction vessel having a polymerization zone containing a bed of growingpolymer particles. The fluidized bed may be maintained solely by theupwardly flowing gases or may be a stirred bed process. Stirred bedprocesses are those in which the stirrer cooperates with an upwardlydirected flow of gases to assist in the fluidization of the polymerparticles. In general, the processes comprise:

a) continuously or intermittently introducing the one or more monomersinto said polymerization zone;

b) continuously or intermittently introducing at least onepolymerization catalyst into said polymerization zone;

c) continuously or intermittently withdrawing polymer product from saidpolymerization zone;

d) continuously withdrawing gases from the polymerization zone,compressing and cooling said gases for recycle to the polymerizationzone; and

e) continuously maintaining sufficient gas flow through thepolymerization zone to maintain the bed in a fluidized state, said gasflow Comprising recycle of at least a portion of the gases withdrawnfrom the polymerization zone, wherein at least one Liquid Component isprovided in the polymerization zone. A bed is fluidized wheresubstantially all the particles in the bed are suspended in the gas andthe particles behave like a fluid.

In one preferred embodiment of the invention, the Liquid Component isprovided in the polymerization zone in an amount greater than that whichcan be absorbed by the polymer particles, and the amount of the LiquidComponent that is in excess of the amount that can be absorbed by thepolymer particles, is capable of being in the liquid phase throughoutthe polymerization zone. Preferably, the Liquid Component is provided inan amount of at least 1 percent by weight based upon the weight of thebed.

In another preferred embodiment, the Liquid Component is providedthroughout the polymerization zone in liquid and gaseous phases, and ispresent in the gases in an amount sufficient that substantially no netvaporization of liquid phase Liquid Component into the gaseous mediumoccurs in the polymerization zone. Thus, the amount of Liquid Componentin the liquid phase in the polymerization zone is substantially constantunder steady state operating conditions.

In another preferred embodiment, sufficient liquid component is providedto enable the bed to be reduced in height to a level below that whichcould be obtained by substantially the same process but having theliquid component replaced with an inert, non-condensable gas. The liquidcomponent in the gas and on or in the polymer particles cansignificantly change the fluidization properties such that thisturn-down can be achieved. The turn down enables transitions from onecatalyst or polymer to another to be achieved rapidly and with theproduction of minimal off-grade polymer.

In another preferred embodiment, the Liquid Component permits thepolymerization zone to be operated at a high bed density ratio (“FBD”)(settled bed density divided by fluidized bed density). In thisembodiment, the Liquid Component is provided in the polymerization zonein an amount sufficient to increase the bed density above that achievedby a similar process but in which the liquid component is replaced withan inert, non-condensable gas. Advantageously, the Liquid Component isprovided in an amount such that the bed density is increased by anamount of at least about 10, preferably at least about 20, percent ofthe difference between 1.0 and FBDS wherein FBDS is the bed densityachieved using the inert, noncondensable gas in place of the liquidcomponent.

In another preferred embodiment, the at least one Liquid Component isprovided in an amount such that the gases withdrawn from thepolymerization zone contain at least a portion of the Liquid Componentin the liquid phase.

In another preferred embodiment, the at least one Liquid Component isprovided in an amount sufficient to substantially eliminate thegeneration of static in the polymerization zone.

In another preferred embodiment, the at least one Liquid Component isprovided in an amount sufficient to substantially eliminate or reducethe presence of fines in the gases withdrawn from the polymerizationzone. Preferably, the fines in the gases withdrawn from thepolymerization zone are reduced by at least about 50 weight percent ascompared to those in a similar process but having the Liquid Componentreplaced with inert, non-condensable gas. Often fines having a majordimension of less than about 75 microns, and preferably less than about100 microns, are substantially eliminated from the gases leaving thepolymerization zone as compared to a similar process but not containingthe Liquid Component.

Another preferred embodiment of this invention relates to producingpolymer particles that are sticky at the temperature of thepolymerization zone. In this aspect, the at least one Liquid Componentis provided in an amount sufficient to substantially prevent undueagglomeration of polymer particles in the polymerization zone. Undueagglomeration results in the formation of particles that are so large asto disrupt the fluidization of the bed or cause fouling of the reactionvessel walls or are larger than desired for polymer product. Generally,unduly large agglomerates have a major dimension greater than about 5,sometimes greater than about 2, centimeters. In this feature of theinvention, the Liquid Component preferably has a limited solubilityinthe polymer and the Liquid Component is provided in an amount in excessof that which can be dissolved in the polymer in the polymerizationzone.

Another preferred embodiment of the invention relates to the productionof polymer, wherein upon loss of the gas flow to maintain the bedfluidized and the polymer particles settle in the presence of monomer,the exothermic polymerization reaction can continue and increase thetemperature of the polymer particles to a temperature at which theparticles stick together or fuse. In this feature, the at least oneLiquid Component is provided in an amount sufficient to delay or preventan increase in the temperature within the settled polymer bed to atemperature at which the unfluidized particles fuse. If the unduetemperature rise is delayed, the delay should be for a time sufficientto introduce a kill agent to stop the polymerization, e.g., for at leastabout 5 minutes, preferably, at least about 10 minutes. Kill agents arewell known in the art. Preferably, the Liquid Component is provided inan amount sufficient to prevent localized fused regions greater thanabout 30 centimeters in major dimension, from forming.

Beyond the reduced risk of polymer fusion one can take further advantageof this feature of the invention by increasing the polymerization zonetemperature closer to the particle fusing temperature. In commercialfluid bed operations a healthy temperature margin is often left betweenthe polymerization zone temperature and the polymer fusing temperatureto avoid the risk of fusing. Increasing the polymerization zonetemperature enables a greater polymer production rate out of existing ornew equipment than would be obtained at lower temperatures. This occursdue to the greater heat removal capacity due to a greater temperaturedifference between the recycle gas stream and the cooling watertemperature. Furthermore this enables catalysts to be operated at highertemperatures than were possible before without undue risk of polymerfusion. Some catalysts will have higher productivity or otherperformance advantages and/or make better products in the newlyaccessible temperature region.

In another preferred embodiment of the invention, the at least oneLiquid Component is provided in an amount sufficient to enhance theproduction rate of polymer, even at the same average bulk temperature inthe polymerization zone. Preferably, the observed increase in productionrate is at least about 5 percent as compared to that provided bysubstantially the same process but replacing the at least one LiquidComponent with an inert, non-condensing gas, wherein the dew point ofsaid at least one Liquid Component under the conditions of thepolymerization zone is within about 2° C. of the average bulktemperature of the polymerization zone.

Another preferred embodiment of this invention relates to processesdeleteriously high localized temperatures can be generated due to theexothermic nature of the polymerization reaction. These temperaturesmay, for example, tend to deactivate the catalyst or accelerate thepolymerization reaction to a level where the heat removal capacities areinsufficient to control temperature. In this feature, the at least oneLiquid Component is provided in an amount sufficient to protect thecatalyst from deleteriously high, localized temperatures. Hot spots canbe avoided in that heat generated by the polymerization is absorbed bythe mass of Liquid Component present and, if the Liquid Component iscapable of being vaporized, is consumed in the vaporization of at leasta portion of the Liquid Component in the region. Some or substantiallyall the Liquid Component that is vaporized may condense in the coolersections of the polymerization zone or outside the polymerization zone.In a preferred embodiment, where highly active spots exist on thecatalyst and localized generation of heat increases, the LiquidComponent is vaporized to prevent unduly deleterious high temperaturesfrom being achieved. In some instances, where localized regions of heatare generated that cause growing polymer particles to undergo undueagglomeration, the volume increase associated with the vaporization ofLiquid Component may physically break apart the agglomerate andfacilitate cooling of the region by the fluidizing gases.

Another preferred embodiment of this invention relates to processes forproducing copolymer by the reaction of two or more monomers. Themonomers may be continuously or intermittently introduced simultaneouslyor separately into the polymerization zone. The at least one LiquidComponent, where sorbed on and in the growing polymer particles, iscapable of affecting the rate of incorporation into the polymer of atleast one monomer as compared to at least one other monomer. Forinstance, the Liquid Component sorbed on the growing particles may berich in one or more of the monomers as compared to at least one other ofthe monomers as a means to promote preferential monomer incorporation.By way of example, one or more monomers may have preferential solubilityin the Liquid Component and thus affect comonomer concentration at thecatalytic site and its relative rate of incorporation into the polymeron a continuous basis. In one embodiment, the Liquid Component maybecome depleted of this monomer and thus the composition of the polymerparticle may change during the time that it is in the polymerizationzone, and a given polymer chain may have differing amounts of comonomerincorporation over its length. In a preferred embodiment of this aspectof the invention, ethylene is a monomer and the at least one othermonomer has a reactive olefinic bond and from 3 to 36 carbon atoms.

Another preferred embodiment of this invention facilitates or enablesthe use of polymerization catalysts that are solution, ionic orfree-radical catalysts in a gas phase process. In this feature, the atleast one Liquid Component is in contact with the catalyst in an amountsufficient for the catalyst to effect the polymerization. Thus, theLiquid Component provides the media to enable the catalyst to functionor function more effectively.

BRIEF DESCRIPTION OF THE DRAWING

The drawing is a schematic depiction of an apparatus suitable forcarrying out processes in accordance with this invention.

DETAILED DESCRIPTION OF THE INVENTION

A Liquid Component that can be used in accordance with this invention isa material that is capable of being in the liquid phase under thetemperature and pressure in the reaction zone taking into account thematerials and concentrations in the reaction zone. One way of expressingwhether or not a component is capable of being in the liquid phase is byreference to its dew point in the environment. The dew point is thetemperature at which a gaseous medium containing a component becomessaturated in the component.

Thus, the dew point takes into account temperature, pressure andphysical properties of other gases in the gaseous medium. At atemperature at or below the dew point of a component in the gaseousmedium, a component in the liquid phase will not evaporate or vaporizeinto the gaseous medium, but it will vaporize or evaporate if thetemperature of the gaseous medium is above the dew point. If the gaseousmedium contains greater than a saturation amount of a component, anamount Of the component in excess of the saturation amount shouldcondense out or precipitate from the gaseous medium. A gas phasepolymnerization zone is a dynamic system with localized temperaturevariations, continuously replenished gases for fluidization, reactionsoccurring and the like and thus a calculated dew point, which reflectsan equilibrium system, may not accurately portray conditions within thepolymerization zone. Hence, under steady state conditions in thepolymerization zone, liquid can be present throughout the polymerizationzone even though the temperature is above the calculated dew point forthe liquid in the gaseous medium under the conditions of thepolymerization zone. The highest average bulk temperature of thepolymerization zone at which, in the presence of Liquid Component in theliquid phase, no net vaporization of liquid into the gaseous mediumoccurs under steady state operating conditions, is referred to as thepractical dew point. Usually, the practical dew point is no more than 2°C., and sometimes no more than 0.5° C., below the calculated dew point.Unless otherwise stated, reference to dew point will be to thecalculated dew point.

The Liquid Component is provided in the polymerization zone in anamount, or concentration, sufficient that under the conditions in thereaction zone, the practical dew point of the Liquid Component in thefluidizing gases is approximately at the average bulk temperature of thepolymerization zone, but not in an amount, or concentration, thatadversely affects the fluidization of the bed. Usually, the LiquidComponent is provided in an amount, or concentration, such that itscalculated dew point in the fluidizing gases under the conditions of thepolymerization zone is within about 2° C., preferably within about 0.5°C., of the average bulk temperature of the reaction zone.

While a characteristic of commercial scale fluidized or stirred bedsthat are fluidized by a gas, is a relative uniformity of temperaturethroughout the bed due to the circulating currents of fluidizedparticles and the passage of the large volume of gases through the bedthat is necessary for maintaining the fluidized state, localizedtemperature differentials can and often do exist. For purposes of thisinvention, the average bulk temperature of the reaction zone isdetermined by the average of the temperature of the reaction zone at amid point (the region between 30 to 70 percent of the weight of the bed)and the temperature at or slightly above the top of the bed. In theevent that adequate temperature sensors are not provided to ascertainthe average bulk temperature, the average bulk temperature can beestimated as the temperature of the gases in the region proximate to thetop of the bed.

The pressure in the polymerization zone changes over the bed height. Thepressure for purposes of the calculated dew point calculation is thepressure of the gases leaving the top of the polymerization zone.

The amount, or concentration, of the Liquid Component is below thatwhich would adversely affect the fluidization properties in the bed.Adverse effects include promotion of undue agglomeration of fluidizedpolymer particles (either within the bed or on the walls of the reactionvessel) and undue disengagement of Liquid Component from the fluidizedbed such as evidenced by Liquid Component pooling at the bottom of thereaction zone or reaction vessel. Preferably, the Liquid Component isprovided in an amount not exceeding that where the gaseous phase wouldcease to be the continuous phase in the polymerization zone, i.e., a gasphase has a continuous path through the polymerization zone.

The Liquid Component may be present in the polymerization zone both inthe vapor phase and liquid phase, and only Liquid Components that have avery low vapor pressure will be, for all practical purposes, essentiallyentirely in the liquid phase. The liquid phase may be in the form of afree liquid droplet or liquid adsorbed or absorbed on the polymerparticle or a combination thereof. Absorbed Liquid Component is thatwhich enters into a chemical reaction or has a chemical interaction orassociation with the polymer. Absorbed Liquid Component may be inequilibrium with Liquid Component in the gas phase, but, all otherthings being equal, the mole fraction in an inert, non-condensable gasthat is in equilibrium with the absorbed Liquid Component will besubstantially less than that the mole fraction in equilibrium with theLiquid Component per se. Hence, Absorbed Liquid Component implies morethan having a Liquid Component that is miscible with the polymer.Adsorbed Liquid Component is liquid that resides on the polymer byphysical attraction or occlusion.

Absorbed Liquid Component does not generally have a material effect ondew point calculations and can often be excluded from calculationsdetermining the dew point based upon total Liquid Component in thepolymerization zone. Thus, if the polymer present in the polymerizationzone is capable of absorbing 5 kilograms of Liquid Component and at theconditions of the polymerization zone, the gases would be saturated withLiquid Component at a content of 7 kilograms of Liquid Component, then12 kilograms of Liquid Component must be provided to operate thepolymerization zone at its dew point. Any additional Liquid Componentabove 12 kilograms would essentially be adsorbed or free LiquidComponent.

The total amount of liquid on a polymer particle less that amount whichcan be dissolved in the polymer is the adsorbed liquid. Depending uponthe polymer being formed and the processing conditions, significantinterstitial void volume may exist within a polymer particle. This voidspace may increase if the polymer is solvated, for example, with theLiquid Component. Hence, frequently, from about 15 to 25 volume percentof the polymer particle may be void space and available for adsorptionof Liquid Component.

In an advantageous embodiment of this invention, the Liquid Component ispresent in an amount such that its liquid phase is substantiallyentirely on or in the polymer particles in the bed. In anotheradvantageous embodiment, Liquid Component is present as fine droplets inthe polymerization zone, e.g., as a fog. In order to form the fog, theliquid droplets are of a size that enables a relatively stablesuspension of the droplets in the upwardly flowing gases, i.e., thedroplets have a settling velocity that is relatively low in comparisonto the velocity of the gases. Generally, where present, the liquiddroplets are less than about 10 microns in diameter. The fog flowssubstantially with the fluidizing gases and is recirculated to thepolymerization zone. Typically, the fog comprises less than about 20,often less than about 10, weight percent Liquid Component in the liquidphase, based on the total weight of the gas phase and entrained liquid.The presence of liquid phase Liquid Component in the gases withdrawnfrom the polymerization zone can, in some instances, assist inminimizing fouling of piping and equipment for recycling the gases, andadvantageously, the Liquid Component is provided in an amount sufficientto such reduce fouling. If desired to minimize potential damage to acompressor for recycling gases to the polymerization zone, the gases maybe preheated to reduce the amount of liquid present prior to introducingthem into the compressor.

Any Liquid Component that is in the gaseous phase in the gases withdrawnfrom the polymerization zone may be recycled to the polymerization zone.This vaporous Liquid Component may be condensed during the processing ofthe recycle stream and, if desired, introduced into the polymerizationzone as a liquid. In some instances, a portion of the liquid phaseLiquid Component may flash upon being introduced into the polymerizationzone and thus serve to cool the polymerization zone.

Often, the liquid phase of the Liquid Component, or the sum of allLiquid Components where more than one is present, is at least about 1,frequently less than about 50, sometimes between about 1 and 40, e.g.,between about 2 and 25, weight percent of the fluidized bed. The weightof the fluidized bed can be calculated from the pressure drop of thegases passing through the bed and the cross-sectional area of the bed.The total amount of Liquid Component in the polymerization zone (thatwhich is gaseous and that which is liquid) may vary widely, especiallyif a substantial portion of the Liquid Component is in the gaseousphase. Generally, the total amount of Liquid Component is at least about1, frequently less than about 75, sometimes between about 1 and 60,e.g., between about 2 and 30, weight percent based on the weight of thefluidized bed. Often, less than about 75, preferably less than about 50,and in many instances, from virtually none to less than 25, weightpercent of the Liquid Component is in the vapor phase in thepolymerization zone.

Materials suitable as the Liquid Component will depend upon the desiredconditions of the polymerization zone. Thus, with higher temperature andlower pressure operations, materials would be excluded that wouldotherwise be suitable in higher pressure or lower temperatureoperations. Another condition affecting the practical dew point is theconcentration of the Liquid Component in the reaction zone. For example,Liquid Components requiring unduly high concentrations in the vaporphase to achieve a calculated dew point at or above the conditions inthe reaction zone, may be impractical in commercial operations. If theconcentration of liquid is allowed to increase to a point wherefluidization is lost, the reaction will cease to be a gas or vapor phasereaction which will lead to a catastrophic collapse of the fluidizedbed.

The Liquid Component may be reactive or substantially non-reactive inthe polymerization reactions; however, the Liquid Component should notunduly adversely affect the polymerization catalysts, the polymerizationreaction or the polymer product, especially morphology and otherphysical properties. Environmental and toxicological issues may alsoplay roles in the selection of the Liquid Component. Illustrative LiquidComponents include substantially inert chemical compounds, solvents forone or more monomers or additives to the polymerization zone, monomers,and polymers for physical or chemical incorporation into the polymerproduct, e.g., substituted and unsubstituted alkanes, alkenes,alkadienes, cycloaliphatics, and aromatics of up to 30 carbons, e.g.,propane, propylene, butane, isobutane, butene-1, butene-2, isobutene,1,2-butadiene, 1,3-butadiene, n-pentane, pentene-1, pentene-2,isopentane, n-hexane, 2-methyl pentane, hexene-1, hexene-2, 4-methylhexene, cyclohexane, cyclohexene, benzene, n-heptane, toluene, e-octane,octane-1, xylene, n-decane, decene-1, dodecane, dodecene-1, cetane,mineral oils, hexadecene-1, octadecane, octadecene-1 and the like.Materials containing heteroatoms may also find application as LiquidComponents. The heteroatoms may be one or more of nitrogen, oxygen,silicon, phosphorus, boron, aluminum and sulfur. These Liquid Componentshave up to about 30 carbon atoms and may be non-cyclic or cyclic andinclude amines, ethers, thioethers, phosphines, etc. Exemplary materialsare triethyl amine, triethylene tetraamine, pyridine, piperazine,tetrahydrofuran, diethylether, di-t-butyl ether, silanes, silicone oilsand the like.

Where polyolefins are the polymer product (polyolefins being definedherein as polymers made from monomers having one or more reactivecarbon-carbon unsaturated bonds and thus includes olefins, dienes,trienes, etc.), the Liquid Component may contain one or more monomers.Examples of these monomers include the following:

A. alpha olefins such as ethylene, propylene, butene-1, isobutylene,4-methyl pentene, hexane-1, octene-1, decene-1, dodecene-1, etc. andstyrene.

B. dienes such as hexadiene, vinyl cyclohexene, dicyclopentadiene,butadiene, isoprene, ethylidene norbornene and the like, and

C. polar vinyl monomers such as acrylonitrile, maleic acid esters, vinylacetate, acrylate esters, methacrylate esters, vinyl trialkyl silanesand the like.

In an advantageous embodiment of this invention, the polymer product isa polyolefin, preferably ethylene copolymer, propylene copolymer orpolybutene or butene copolymer, that is made using an alpha olefinmonomer that is procured in combination with non-reactive alkanes andalkenes that are condensable in the polymerization zone. Thus theprocesses of this invention permit the use of less pure, and thus lessexpensive, alpha olefin feeds due to the ability to accommodate liquidin the polymerization zone. Often, the feed stream comprises at leastabout 50, preferably at least about 75, and most frequently at leastabout 90, up to about 95, weight percent reactive alpha olefin with thebalance usually consisting of substantially non-reactive hydrocarbonssuch as alkanesand alkenes. For instance, where butene-1 is a desiredmonomer, the butene process streams may contain about 50 to 95 molepercent butene- 1, 0 to about 40 mole percent isobutene, 0 to about 40mole percent butene-2, 0 to about 40 mole percent butane, and 0 to about40 mole percent isobutane.

In another advantageous aspect, the polymer is polyolefin, particularlyethylene copolymer or propylene copolymer, and at least one comonomer tobe incorporated is a high molecular weight alpha-olefin, e.g., fromabout 12 to 40 carbon atoms. Incorporation of the comonomer providesbeneficial properties to the polyolefin including clarity,processability, strength and flexibility. Indeed, polyethylene can beproduced with high molecular weight olefin to produce a product in thegas phase process that is comparable in performance to the long chainbranched polyethylene obtained by the high pressure process. Sometimesin these processes, the high molecular weight olefin is provided insolution with another Liquid Component to provide desirableconcentrations of the higher molecular weight olefin on the growingcatalyst particle for the sought degree of incorporation. Depending uponthe activity of the catalyst for incorporation of the higher olefin, toogreat a concentration at the catalytic site may effect too muchincorporation and too low a concentration may result in little or noincorporation of the higher olefin into the copolymer. Often, theconcentration of higher olefinin total Liquid Component is at leastabout 0.1 or 0.5, say, between about 1 and 75, frequently between 1 and30, percent by weight based on the weight of the polymer.

In another advantageous aspect of this invention, the Liquid Componentcomprises a polymer, physical or chemical modifier or additive. Sincethe modifiers and additives are present during formation of the polymer,intimate and relatively uniform incorporation can occur. Moreover,energy intensive blending and milling operations may be avoided.Further, the relatively uniform dispersion throughout the polymer mayenable the amount of the additives to be reduced in comparison to theamounts required during blending operations to achieve the same effects.The modifiers and additives should not unduly adversely affect thepolymerization reaction. Generally, the amount of the modifiers andadditives provided by the Liquid Component comprises at least about 10,say, at least about 100, parts per million by weight in the polymerproduct up to about 25, often up to about 15, weight percent of thepolymer product. The amount of additives desired to be incorporated intothe polymer product is within the skill of those of ordinary skill inthe art.

Examples of modifiers and additives that have found application inpolymers include antioxidants, stabilizers, processing aids,fluidization aids, antiblock agents, agents to promote blockiness,latent cross linking agents, grafting agents, compatibilizing agents(for instance, to enable the formation of polymer blends), inorganicsolids, fillers, dyes, pigments, etc. Examples of modifiers andadditives that have found application in polymers include thermo- andphoto-oxidation stabilizers such as hindered phenolic antioxidants,dialkylthioester stabilizers, dialkyldisulfide stabilizers, alkyl oraryl phosphite or phosphonite stabilizers, and hindered amine lightstabilizers; crosslinking agents such as sulfur and sulfur compoundssuch as metallic thiocarbamates, dicumyl peroxide, butyl cumyl peroxideand di-t-butyl peroxide; colorants such as carbon black and titaniumdioxide; fillers or extenders such as calcium carbonate, kaolin, clayand talc; filler coupling reagents such as silanes and titanates;internal and external lubricants or processing aids such as metallicstearates, hydrocarbon waxes, fatty acid amides, glyceryl stearateesters and silicone oils; oil extenders such as parafffinic andnaphthenic mineral oil and silicone oils; grafting reagents such asmaleic anhydride and vinyl silanes; chemical blowing reagents such asmodified azodicarbonamide, azodicarbonamide anddiphenyloxide-4,4′disulphohydrazide; compatibilizing compounds such asblock polymers of either butadiene or other polymerizable hydrocarbons,styrenic, alkyl acrylate or caprolactone segments for example; flameretardants such as brominated or chlorinated organics, hydrated alumina,magnesium hydroxide and antimony oxide; and other conventional materialsthat may be mixed with polymer as desired. Advantageously, additives ormodifiers that would be expected to be solids under the conditions ofthe polymerization zone, e.g., di-n-octyl diphenylamine, may find use inthe processes of this invention by being dissolved or suspended inLiquid Component.

One attractive class of additives that can be used in accordance withthis invention are physical property modifiers, especially forpolyolefins. The properties modified include processability, e.g.,through extrusion; clarity; and freedom from stress cracks. Illustrativemodifiers are mineral oil, dodecylphenol, dodecylbenzene, hexadecane,eicosane, diphenyl(2-ethylhexyl) phosphate, tri(2-ethylhexyl)phosphate,diisoctyl phthalate, di(2-ethylhexyl)phthalate, didecyl phthalate,di-n-octyl phthalate, di-capryl phthalate, turpentine, pine oil,tetralin, di(2-ethylhexyl)adipate, polyethylene glycoldi(2ethylhexoate), didecyl adipate and isooctyl palmate.

Another class of additives that are attractive for use in accordancewith the processes of this invention are polymers, includingprepolymers, that are carried in Liquid Component, either solvated or asa slurry. The polymers can be for blending with the polymer produced orfor reaction with the polymer. In this manner, the properties of theultimate product can be readily optimized. For instance, a polymer froma separate polymerization zone may have a set of properties that cannotbe obtained in the fluid bed polymerization zone of the processes of theinvention, and this polymer can become inherently blended with thepolymer being grown to produce a polymer blend, or alloy.Advantageously, where the polymers to be blended have limitedcompatibility, the Liquid Component contains a mutual solvent orcompatibilizing agent. Alternatively, the polymer introduced into thepolymerization zone has sites reactive under the conditions in thepolymerization zone and a block polymeric structure is produced. As canbe readily appreciated, the processes of this invention permit thelinking of disparate types of polymerization processes with gas phaseprocesses to achieve a balance of product qualities from the introducedpolymer and the economic efficiencies of the gas phase process.Generally, where polymer is introduced, the polymer is at least about 1,often at least about 2, say, about 2 to 60, weight percent of totalpolymer product. One particularly attractive process is producing analloy of polyethylene and polypropylene in a weight ratio of about 10:1to 1:10, say, about 5:1 to 1:5. In this process, one of the polymers,e.g. polypropylene, is introduced into the polymerization zone with acompatibilizing Liquid Component, e.g., mineral oil, and the polymerproduct is an alloy. Also, the processes allow the linking of a solutionor liquid suspension process and a gas phase polymerization processwithout the intermediate need to remove substantially all of the liquidcarried with the polymer from the solution or liquid suspension process.

Liquid Components can enhance the morphology of the polymer product.Morphology falls within three general classes: surface regularity,internal structure and size. In some instances, lack of surfaceregularity of products from fluid bed polymerizations results inhandling difficulties including reduced flowability and tendency toabrade and generate fines. The presence of Liquid Component oftenenhances the production of polymer particles with enhanced surfacemorphology as compared to product made by substantially the same processbut having an inert, non-condensable gas used in place of the LiquidComponent. Often the product of a gas phase polymerization is granularin nature while consumers typically desire pellet form product. To meetconsumer desires, granular product has been processed in pelletizers.The presence of the Liquid Component can make each of the granularparticles more spherical in shape and can promote agglomeration of asmall number of particles to form a pellet-sized polymer product, e.g.,from about 0.5 or 1 to about 10 millimeters in major dimension. Theamount of Liquid Component required will vary depending upon thepolymer, the sought size of the polymer particle and the effectivenessof the Liquid Component as a solvent. If too little or too much LiquidComponent is present, undue agglomeration may occur. For instance, manyLiquid Components have a solvating or swelling effect on the polymer,and if unduly large amounts of Liquid Component are used the polymerparticle may become unduly soft or tacky that large agglomerates orsheeting at the walls of the reaction vessel occur. The solvatingeffect,however, can be a useful characteristic to enhance the morphology of thepolymer product.

Polymers and Catalysts

The practice of this invention is not limited to any particular class orkind of polymerization or catalyst. Any catalyst useful in the conductof gas phase polymerization reactions or that can be used in thepresence of Liquid Component is suitable for use in the practice of thisinvention.

This invention finds particular applicability to the polymerization ofcleans, especially clean polymerization reactions involvinghomopolymerization and copolymerization. The term copolymerization asused herein includes polymerization with two or more different ofmonomers. Advantageougly, the polymerization includes polymerizationwith one or more high boiling monomers. Examples of monomers have beenset forth above.

Where a copolymer is to be made, the Liquid Component can be selected toaffect the relative rates of incorporation of the monomers. Forinstance, one or more monomers may substantially be in the gaseous stateunder the conditions of the polymerization while one or more othermonomers may be substantially in the liquid state under thoseconditions. The Liquid Component may essentially consist of the liquidmonomers or may also comprise a liquid that is miscible with the liquidmonomers. The concentration of the monomers in the Liquid Componentsorbed on the growing catalyst particle can influence the rate ofincorporation of such monomers into the polymer chain. Often, thelighter monomer in making polyolefin copolymers is ethylene or propyleneand the heavier monomer which is at least in part in the liquid phase,is propylene (where ethylene is the comonomer) or higher olefin,e.g., amonomer having at least one reactive olefinic bond and having from 3 toabout 36 carbon atoms. Also, the monomer in the liquid phase maycomprise a prepolymer that is made outside the polymerization zone.Suitable prepolymers are readily discernible to one skilled in the art.The Liquid Component may also have a greater solubility parameter forone or more monomers than one or more other monomers. For example,toluene or n-hexane may be used as a Liquid Component to preferentiallysorb vinyl acetate as compared to ethylene to make an ethylene/vinylacetate copolymer. Other examples include the use of substantiallynon-reactive compounds that are otherwise similar in structure to thecomonomer such as n-hexane for hexene-1 comonomer, noctane for octene-1comonomer, etc.

Catalysts for olefin polymerizations include the conventionalZiegler-Natta catalysts, by which is meant those formed by reacting ametal alkyl or hydride with a transition metal compound, are preferredin the practice of this invention. Those formed by reacting an aluminumalkyl with compounds of metals of groups I to III of the periodic tableare particularly useful.

Illustrative of the catalysts useful in the practice of this inventionare the following:

A. Titanium based catalysts such as those described in U.S. Pat. Nos.4,376,062 and 4,379,758.

B. Chromium based catalysts such as those described in U.S. Pat. Nos.3,709,853; 3,709,954 and 4,077,904.

C. Vanadium based catalysts such as vanadium oxychloride, vanadiumacetylacetonate, and those described in U.S. Pat. No. 4,508,842.

D. Metallocene catalysts such as those described in U.S. Pat. Nos.4,530,914; 4,665,047; 4,752,597; 5,218,071, 5,272,236 and 5,278,272.

E. Cationic forms of metal halides, such as aluminum trihalides.

F. Cobalt catalysts and mixtures thereof such as those described in U.S.Pat. Nos. 4,472,559 and 4,182,814.

G. Nickel catalysts and mixtures thereof such as described in U.S. Pat.Nos. 4,155,880 and 4,102,817.

H. Rare earth metal catalysts and mixtures thereof.

Other catalysts that may find application due to the presence of theLiquid Component include:

A. cationic catalysts, particularly for the polymerization ofisobutylene, styrene, butyl rubber, isoprene rubber and vinyl ethers,such as boron trifluoride (hydrated), aluminum trifluoride, sulfuricacid, hydrochloric acid (hydrated), and titanium tetrachloride;

B. anionic catalysts, particularly for the polymerization of butylrubber, isoprene rubber, styrene and butyl rubber copolymer, andacrylonitrile) such as alkyl lithiums, NaNH2, and LiN(Et)2; and

C. free radical catalysts, particularly for polymerization of butylrubber, isoprene rubber, styrene, vinyl halide, styrene butyl rubbercopolymer, acrylonitrile-butadiene-styrene terpolymer and vinyl esters,such as azobisisobutyronitrile, benzoyl peroxide, acetyl peroxide,t-butyl peracetic acetate, cumyl peroxide, and t-butyl hydroperoxide.

In general, the catalyst used in the mixture of this invention can besoluble or insoluble, supported or unsupported, or spray dried in eitherthe presence or absence of a filler. Alternatively, the polymerizationcatalyst can be introduced to the polymerization zone in the form of aprepolymer using techniques known to those skilled in the art.

When the catalyst is supported, typical supports can include, forexample, silica, carbon black, porous crosslinked polystyrene, porouscrosslinked polypropylene, alumina, thoria, zirconia, or magnesiumhalide (e.g., magnesium chloride) support materials. Silica carbonblack, and alumia are preferred support materials. Silica and carbonblack are the most preferred support materials. A typical silica oralumina support is a solid, particulate, porous material essentiallyinert to the polymerization. It is used as a dry powder having anaverage particle size of about 10 to about 250 microns and preferablyabout 30 to about 100 microns; a surface area of at least 200 squaremeters per gram and preferably at least about 250 square meters pergram; and a pore size of at least about 100 Angstroms and preferably atleast about 200 Angstroms. Generally, the amount of support used is thatwhich will provide about 0.1 to about 1.0 millimole of transition metalper gram of support. In a preferred embodiment, two types of carbonblack are used as support. DARCO G-60 (pH of water extract=5) is used asdry powder having a surface area of 505 square meters per gram, averageparticle size of 100 microns, and porosity of 1.0 to 1.5 cubiccentimeter per gram. NORIT A (pH of water extract=9-11) used as a drypowder has a surface area of 720 square meters per gram, averageparticle size of 45 to 80 microns.

The catalyst can be impregnated on a support by well known means such asby dissolving the metal compound in a solvent or diluent such as ahydrocarbon or tetrahydrofuran in the presence of the support materialand then removing the solvent or diluent by evaporation such as underreduced pressure. Alternatively, the transition metal component can bedissolved in a solvent or diluent such as a hydrocarbon ortetrahydrofuran and spray dried to generate a well-shaped catalystprecursor having little or no silica or other inorganic solids content,if desired.

Among the preferred catalysts useful in this invention are catalystscontaining nickel, titanium, and cobalt, with cobalt and nickelcompounds being the most preferred. Preferred catalysts are organonickelcompounds of nickel with mono- or bi-dentate organic ligands containingup to 20 carbon atoms. “Ligand” is defined as an ion or molecule boundto and considered bonded to a metal atom or ion. Mono-dentate meanshaving one position through which covalent or coordinate bonds with themetal may be formed; bi-dentate means having two positions through whichcovalent or coordinate bonds with the metal may be formed. Theorganonickel compounds are generally soluble in inert solvents. Thus,any salt or an organic acid containing from about 1 to 20 carbon atomsmay be employed. Representative of organonickel compounds are nickelbenzoate, nickel acetate, nickel naphthenate, nickel octanoate, nickelneodecanoate, nickel 2-ethylhexanoate, bis(¹-allyl nickel),bis(¹-cycloocta-1,5-diene), bis(¹-allyl nickel trifluoroacetate),bis(a-furyl dioxime) nickel, nickel palmitate, nickel stearate, nickelacetylacetonate, nickel salicaldehyde, bis(salicyladehyde) ethylenediimine nickel, bis(cyclopentadiene) nickel, cyclopentadienylnickelnitrosyl and nickel tetracarbonyl. The preferred component containingnickel is a nickel salt of a carboxylic acid or an organic complexcompound of nickel.

Co-catalysts that can be employed with the component useful in thepractice of this invention are organoaluminum compounds such astriethylaluminum (TEAL), triisobutylaluminum (TIBA), diethyl aluminumchloride (DEAC), partially hydrolyzed DEAC, methylaluminoxane (MAO), ormodified methylaluminoxane (MMAO). When MAO or MMAO is employed as theco-catalyst, it may be one of the following: (a) branched or cyclicoligomeric poly(hydrocarbylaluminum oxide)s which contain repeatingunits of the general formula —(Al(R′″)O)—, where R′″ is hydrogen, analkyl radical containing from 1 to about 12 carbon atoms, or an arylradical such as a substituted or unsubstituted phenyl or naphthyl group;(b) ionic salts of the general formula [A⁺][BR*4⁻], where A⁺is acationic Lewis or Bronsted acid capable of abstracting an alkyl,halogen, or hydrogen from the transition metal component of thecatalyst, B is boron, and R* is a substituted aromatic hydrocarbon,preferably a perfluorophenyl radical; and (c) boron alkyls of thegeneral formula BR*₃, where R* is as defined above.

Preferably, the co-catalyst is a branched or cyclic oligomericpoly(hydrocarbylaluminum oxide). More preferably, the co-catalyst is analuminoxane such as methylaluminoxane (MAO) or modifiedmethylaluminoxane (MMAO).

Aluminoxanes are well known in the art and comprise oligomeric linearalkyl aluminoxanes represented by the formula:

and oligomeric cyclic alkyl aluminoxanes of the formula:

wherein s is 1 to 40, preferably 10 to 20; p is 3 to 40, preferably 3 to20; and R′″ is an alkyl group containing 1 to 12 carbon atoms,preferably methyl or an aryl radical such as a substituted orunsubstituted phenyl or naphthyl radical. MAO and MMAO and the like canalso be employed as a co-catalyst with a metallocene catalyst system.

Promoters that are useful in combination with nickel catalyst systemsinclude hydrogen fluoride (HF), borontrifluoride (BF₃), etherates (ordiethylether) of HF and BF₃. HF or BF₃ can also be used without anetherate.

Promoters that can be used with titanium containing catalysts includeiodine, and organic ethers such as diphenylethers (DPE). For isoprene,the combination TiCl₄, TIBA, and DPE is employed.

Useful cobalt catalysts include the cobalt salts of organic acids,cobalt complexes and the like. The preferred cobalt catalysts includecobalt b-ketone complexes, for example, cobalt (II) acetylacetonate andcobalt (III) acetylacetonate; cobalt b-ketoacid ester complexes, forexample, cobalt acetacetic ethylester complexes; cobalt salts of organiccarboxylic acids having 6 or more carbon atoms, for example, cobaltoctoate, cobalt naphthenate, and cobalt benzoate; and cobalt halidecomplexes, for example, cobalt chloride-pyridine complexes; cobaltchloride-ethyl alcohol complexes and cobalt complexes coordinated withbutadiene, for example, (1,3-butadiene)[1-(2-methyl-3-butenyl)-¹-allyl]-cobalt which may be prepared, forexample, by mixing a cobalt compound with an organic aluminum compound,organic lithium compound or alkyl magnesium compound and 1,3-butadiene.Other typical cobalt catalysts compounds are cobalt sorbate, cobaltadipate, cobalt 2-ethylhexoate, cobalt stearate, and the like compoundswherein the organic portion of the molecule contains about 5 to 20,preferably 8 to 18 carbon atoms and one or two carboxylic functions, aswell as acetylacetonate.

Co-catalysts that can be employed with catalysts containing cobalt,include ethylaluminum sesquichloride (EASC), ethylaluminum dichloride(EADC), or partially hydrolyzed DEAC (DEACO), MAO and mixtures thereof.Water in small amounts can be used as a promoter with the cobaltcontaining catalysts.

Inert Particulate Material

Optimal fluidization aids that can be employed in the invention areinert particulate materials which are chemically inert to the reaction.Examples of such fluidization aids include carbon black, silica, claysand other like materials such as talc. Organic polymeric materials canalso be employed as a fluidization aid. Carbon blacks and silicas arethe preferred fluidization aids with carbon black being the mostpreferred. The carbon black materials employed have a primary particlesize of about 10 to 100 nanometers and an average size of aggregate(primary structure) of about 0.1 to about 10 microns. The specificsurface area of the carbon black is about 30 to 1,500 m2/gm and thecarbon black displays a dibutylphthalate (DBP) absorption of about 80 toabout 350 cc/100 grams.

Silicas which can be employed are amorphous and have a primary particlesize of about 5 to 50 nanometers and an average size of aggregate ofabout 0.1 to 10 microns. The average size of agglomerates of silica isabout 2 to about 120 microns. The silicas employed have a specificsurface area of about 50 to 500 m2/gm and a dibutylphthalate (DBP)absorption of about 100 to 400 cc/100 grams.

Clays which can be employed according to the invention have an averageparticle size of about 0.01 to about 10 microns and a specific surfacearea of about 3 to 30 m2/gm. They exhibit oil absorption of about 20 toabout 100 gms per 100 gms.

Organic polymeric substances which can be used include polymers andcopolymers of ethylene, propylene, butene, and other alpha olefins aswell as polystyrene, in granular or powder form, can also be utilized.These organic polymeric materials have an average particle size rangingfrom about 0.01 to 100 microns, preferably 0.01 to 10 microns.

The amount of fluidization aid utilized generally depends on the type ofmaterial utilized and the type of polybutadiene or polyisopreneproduced. When utilizing carbon black or silica as the fluidization aid,they can be employed in amounts of about 0.3% to about 50% by weight,preferably about 5% to about 30% based on the weight of the finalproduct (polybutadiene or polyisoprene) produced. When clays or talcsare employed as the fluidization aid, the amount can range from about0.3% to about 80% based on the weight of the final product, preferablyabout 12% to 75% by weight. Organic polymeric materials, other alphaolefins or polystyrene are used in amounts of about 0.1% to about 50% byweight, preferably about 0.1% to about 10% based on the weight of thefinal polymer product produced. It is understood that the smaller thesize of the fluidization aid employed, the greater the amount employedin the process of the invention.

The fluidization aid can be introduced into the reactor at or near thetop of the reactor, at the bottom of the reactor, or to the recycle linedirected into the bottom of the reactor. Preferably, the fluidizationaid is introduced at or near the top of the reactor or above thefluidized bed. It is preferred to treat the fluidization aid prior toentry into the reactor to remove traces of moisture and oxygen. This canbe accomplished by purging the material with nitrogen gas and heating byconventional procedures. The fluidization aid can be added separately orcombined with one or more monomers, or with a soluble unsupportedcatalyst. Preferably, the fluidization aid is added separately.

A fluidized bed reaction system which is particularly suited toproduction of polymeric materials in accordance with the presentinvention is illustrated in the drawing. With reference thereto, thereactor 10 consists of a reaction zone 12 and a velocity reduction zone14.

In general, the height to diameter ratio of the reaction zone can varyin the range of about 2.7:1 to about 4.6:1. The range, of course, canvary to larger or smaller ratios and depends upon the desired productioncapacity. The cross-sectional area of the velocity reduction zone 14 istypically within the range of about 2.6 to about 2.8 multiplied by thecross-sectional area of the reaction zone 12.

The reaction zone 12 includes a bed of growing polymer particles, formedpolymer particles and a minor amount of catalyst particles fluidized bythe continuous flow of polymerizable and modifying gaseous components inthe form of make-up feed and recycle fluid through the reaction zone. Tomaintain a viable fluidized bed, the superficial gas velocity throughthe bed must exceed the minimum flow required for fluidization, andpreferably is at least 0.1 ft./sec above minimum flow. Ordinarily, thesuperficial gas velocity does not exceed 5.0 ft.sec and usually no morethan 2.5 ft./sec is sufficient.

It is essential that the bed always contain particles to prevent theformation of localized “hot spots” and to entrap and distribute catalystthroughout the reaction zone. On start up, the reactor is usuallycharged with a base of particulate polymer particles before gas flow isinitiated such particles may be identical in nature to the polymer to beformed or they may be different. When different, they are withdrawn withthe desired formed polymer particles as the first product. Eventually, afluidized bed of desired polymer particles supplants the start-up bed.

A partially or totally activated precursor composition and/or catalystused in the fluidized bed is preferably stored for service in areservoir 16 under a blanket of a gas which is inert to the storedmaterial, such as nitrogen or argon.

Fluidization is achieved by a high rate of fluid recycle to and throughthe bed, typically in the order to about 50 times the rate of feed ofmake-up fluid. The fluidized bed has the general appearance of -a densemass of individually moving particles as created by the percolation ofgas through the bed. The pressure drop through the bed is equal to orslightly greater than the weight of the bed divided by thecross-sectional area. It is thus dependent on the geometry of thereactor.

Make-up fluid is fed to the bed at point 18. The composition of themake-up stream is determined by a gas analyzer 21. The gas analyzerdetermines the composition of the recycle stream and the composition ofthe make-up stream is adjusted accordingly to maintain an essentiallysteady state gaseous composition within the reaction zone.

The gas analyzer is a conventional gas analyzer which operates in aconventional manner to determine the recycle stream composition tofacilitate maintaining the ratios of feed stream components. Suchequipment is commercially available from a wide variety of sources. Thegas analyzer 21 is typically positioned to receive gas from a samplingpoint located between the velocity reduction zone 14 and heat exchanger24.

The higher boiling monomers can be introduced into the polymerizationzone in various ways including direct injection through a nozzle (notshown in the drawing) into the bed or by spraying onto the top of thebed through a nozzle (not shown) positioned above the bed, which may aidin eliminating some carryover of fines by the cycle gas stream. If therate of consumption is relatively small, heavier monomers can beintroduced into the polymerization zone simply by suspension in thecycle gas stream entering the bottom of the reactor.

To ensure complete fluidization, the recycle stream and, where desired,part of the make-up stream are returned through recycle line 22 to thereactor at point 26 below the bed. There is preferably a gas distributorplate 28 above the point of return to aid in fluidizing the bed. Inpassing through the bed, the recycle stream absorbs the heat of reactiongenerated by the polymerization reaction.

A portion of the fluidizing stream which has not reacted in the bed isremoved from the polymerization zone, preferably by passing it intovelocity reduction zone 14 above the bed where entrained particles candrop back into the bed.

The recycle stream is compressed in a compressor 30 and then passedthrough a heat exchange zone where heat is removed before it is returnedto the bed. The heat exchange zone is typically a heat exchanger 24which can be of the horizontal or vertical type. If desired, severalheat exchangers can be employed to lower the temperature of the cyclegas stream in stages. It is also possible to locate the compressordownstream from the heat exchanger or at an intermediate point betweenseveral heat exchangers. Air cooling, the recycle stream is returned tothe reactor at its base 26 and to the fluidized bed through gasdistributor plate 28. A gas deflector 32 is preferably installed at theinlet to the reactor to prevent contained polymer particles fromsettling out and agglomerating into a solid mass and to prevent liquidaccumulation at the bottom of the reactor as well to facilitate easytransitions between processes which contain liquid in the cycle gasstream and those which do not and vice versa. Illustrative of gasdeflectors suitable for this purpose is the apparatus described in U.S.Patent No. 4,933,149.

The selected temperature of the bed is maintained at an essentiallyconstant temperature under steady state conditions by constantlyremoving the heat of reaction. No noticeable temperature gradientappears to exist within the upper portion of the bed. A temperaturegradient will exist in the bottom of the bed in a layer of about 6 to 12inches, between the temperature of the inlet fluid and the temperatureof the remainder of the bed.

The conditions for olefin polymerizations vary depending upon themonomers, catalysts and equipment availability. The specific conditionsare known or readily derivable by those skilled in the art. Generallythe temperatures are within the range of −10° C. to 120° C., often about15° C. to 90° C., and pressures are within the range of 0.1 to 100, say,about 5 to 50, bar.

Due to the presence of the Liquid Component, the processes of thisinvention may be useful for the preparation of condensation polymers.Polymers prepared by condensation processes include polyamides,polyesters, polyurethanes, polysiloxanes, phenol-formaldehyde polymers,ureaformaldehyde polymers, melamine-formaldehyde polymers, cellulosicpolymers and polyacetals. These processes are characterized by theelimination Of a lower molecular weight by product such as water ormethanol. Since the condensation reactions are generally equilibriareactions, the gas phase operation can assist in the removal of thelighter, and much more volatile, by products. In condensationpolymerizations, it is generally preferred to provide a growing polymerparticle on which Liquid Component comprising one or more of themonomers, is sorbed. In some instances, porous supports may be used tohold Liquid Component and the porous supports are fluidized. The polymerparticle may grow within the porous supports or the reaction may proceedby phase transfer mechanisms in which at least one monomer is within theLiquid Component and at least one monomer in the gas phase with polymergrowth occurring at the liquid/gas interface.

In some instances, it may be desired to provide as a portion of theLiquid Component, a material that binds the byproduct. For instance, ifwater is the by-product, the Liquid Component may comprise a dehydratingcomponent or azeotrope-forming agent or organic anhydride compound,e.g., methanol, to dehydrate the reaction medium. The condensationpolymerization reactions are frequently conducted at temperaturesbetween about 60° and 250° C. and under pressures of up to about 100bar. In general, lower pressures are preferred to favor the eliminationof the by product. The processes may involve the use of catalystsincluding alkaline and acidic catalysts. These catalysts and theiroperating conditions are well known to those skilled in the art.Examples of catalysts are acetic anhydride, sulfonic acid,p-toluenesulfonic acid, sulfuric acid, hydrochloric acid, calciumhydroxide, calcium alkoxides, sodium hydroxide, sodium alkoxide,hydroxides and alkoxides of transition metals, antimony compounds,alkaline salts of zinc, magnesium, aluminum, and the like.

In the processes of this invention, an inert gas can be cycled throughthe reactor. Suitable inert materials for this purpose include nitrogenand saturated hydrocarbons which remain gaseous at a temperature belowthe temperature selected to be maintained in the polymerization zone.Desirably, the total of the partial pressures of all components in thecycle gas stream is sufficient to allow enough gas to be present in thecycle gas stream to permit practical, steady state, continuousoperation. Suitable for this purpose are inert gases such as nitrogen,argon, neon, krypton and the like. Also useful are saturatedhydrocarbons such as ethane, propane, butane and the like as well ashalogen substituted alkanes such as freon. Other materials which remaingaseous under the desired conditions, such as carbon dioxide, providedthey are essentially inert and do not affect catalyst performance, canalso be employed.

Nitrogen, because of its physical properties and relatively low cost isa preferred medium for the manufacture of polymers from higher boilingmonomers such as styrene, vinyl acetic acid, acrylonitrile,methylacrylate, methylmethacrylate and the like. Alkanes such as ethaneand propane which remain gaseous at relatively low temperatures are alsopreferred.

In accordance with our invention the Liquid Component can be directlyintroduced into the polymerization zone or carried into thepolymerization zone as with the recycle gas stream or catalyst orcocatalyst (where used) feed. For example, the Liquid Component may besprayed over the top of the fluidized or stirred bed and thus assist inremoval of entrained particles from the gases leaving the bed. If anexpanded zone is present in the reaction vessel to assist in removal ofparticles in the gases leaving the bed, Liquid Component may becontacted with its surfaces to remove any polymer particles that may beadhering thereto. Liquid Component may be sprayed into the bed in one ormore locations. Liquid Component may also be contacted with and wash thewalls of the reaction vessel surrounding the polymerization zone toassist in removing particles. The Liquid Component may also assist inadhering catalyst to the growing polymer particles to enhance furthergrowth of the particles to desired sizes.

The Liquid Component can be introduced into the polymerization zone invarious ways including direct injection through a nozzle (not shown inthe drawing) into the bed or by spraying onto the top of the bed througha nozzle (not shown) positioned above the bed, which may aid ineliminating some carryover of fines by the cycle gas stream. The LiquidComponent can be introduced into the polymerization zone simply bysuspension in the cycle gas stream entering the bottom of the reactor.

To ensure complete fluidization, the recycle stream and, where desired,part of the make-up stream are returned through recycle line 22 to thereactor at point 26 below the bed. There is preferably a gas distributorplate 28 above the point of return to aid in fluidizing the bed. Inpassing through the bed, the recycle stream absorbs the heat of reactiongenerated by the polymerization reaction.

The portion of the fluidizing stream which has not reacted in the bed isremoved from the polymerization zone, preferably by passing it intovelocity reduction zone 14 above the bed where entrained particles candrop back into the bed.

The recycle stream is compressed in a compressor 30 and then passedthrough a heat exchange zone where heat is removed before it is returnedto the bed. The heat exchange zone is typically a heat exchanger 24which can be of the horizontal or vertical type. If desired, severalheat exchangers can be employed to lower the temperature of the cyclegas stream in stages. It is also possible to locate the compressordownstream from the heat exchanger or at an intermediate point betweenseveral heat exchangers. After cooling, the recycle stream is returnedto the reactor at its base 26 and to the fluidized bed through gasdistributor plate 28. A gas deflector 32 is preferably installed at theinlet to the reactor to prevent contained polymer particles fromsettling out and agglomerating into a solid mass and to prevent liquidaccumulation at the bottom of the reactor as well to facilitate easytransitions between processes which contain liquid in the cycle gasstream and those which do not and vice versa. Illustrative of gasdeflectors suitable for this purpose is the apparatus described in U.S.Pat. No. 4,933,149.

The selected temperature of the bed is maintained at an essentiallyconstant temperature under steady state conditions by constantlyremoving the heat of reaction. Generally, no noticeable temperaturegradient appears to exist within the upper portion of the bed. Atemperature gradient will exist in the bottom of the bed in a layer ofabout 6 to 12 inches, between the temperature of the inlet fluid and thetemperature of the remainder of the bed.

Good gas distribution plays an important role in the operation of thereactor. The fluidizedbed contains growing and formed particulatepolymer particles, as well as catalyst particles. As the polymerparticles are hot and possibly active, they must be prevented fromsettling, for if a quiescent mass is allowed to exist, any activecatalyst contained therein may continue to react and cause fusion.Diffusing recycle fluid through the bed at a rate sufficient to maintainfluidization throughout the bed is, therefore, important.

Gas distribution plate 28 is a preferred means for achieving good gasdistribution and may be a screen, slotted plate, perforated plate, aplate of the bubble-cap type and the like. The elements of the plate mayall be stationary, or the plate may be of the mobile type disclosed inU.S. Pat. No. 3,298,792. Whatever its design, it must diffuse therecycle fluid through the particles at the base of the bed to keep thebed in a fluidized condition, and also serve to support a quiescent bedof resin particles when the reactor is not in operation.

The preferred type of gas distributor plate 28 is metal and has holesdistributed across its surface. The holes are normally of a diameter ofabout ½ inch. The holes extend through the plate. Over each hole thereis positioned a triangular angle iron identified as 36 which is mountedon plate 28. The angle irons serve to distribute the flow of fluid alongthe surface of the plate so as to avoid stagnant zones of solids. Inaddition they prevent the polymer from flowing through the holes whenthe bed is settled.

Any fluid inert to the catalyst and reactants can also be present in therecycle stream. An activator compound, if utilized, is preferably addedto the reaction system downstream from heat exchanger 24, in which casethe actuator be fed into the recycle system from dispenser 38 throughline 40.

In the practice of this invention operating temperatures can extend overa range of from about −100° C. to about 150° C. with temperaturesranging from about 20° or 40° C. to about 120° C. being preferred.

The fluid-bed reactor can be operated at pressures up to about 1000 psi(3895 kPa) and preferably at a pressure of from about 100 psi (390 kPa)to about 350 psi (2413 kPa), for polyolefin resin production. Operationat higher pressures favors heat transfer as an increase in pressureincreases the unit volume heat capacity of the gas.

The partially or totally activated precursor composition and co-catalyst(hereinafter collectively referred to as catalyst) is injected into thebed at a rate equal to its consumption at a point 42 which is abovedistributor plate 28. Preferably, the “catalyst is injected at a pointin the bed where good mixing with polymer particles occurs. Injectingthe catalyst at a point above the distribution plate providessatisfactory operation of a fluidized bed polymerization reactor.Injection of the catalyst into the area below the distributor platecould cause polymerization to begin there and eventually cause pluggingof the distributor plate. Injection directly into the fluidized bed aidsin distributing the catalyst uniformly throughout the bed and tends toavoid the formation of localized spots of high catalyst concentrationwhich can cause “hot spots” to form. Injection of the catalyst into thereactor above the bed can result in excessive catalyst carryover intothe recycle line where polymerization can occur leading to plugging ofthe line and heat exchanger.

The catalyst can be injected into the reactor by various techniques. Itis preferred, however, to continuously feed the catalyst into thereactor utilizing a catalyst feeder as disclosed; e.g., in U.S. Pat. No.3,779,712. The catalyst is preferably fed into the reactor at a point 20to 40 percent of the reactor diameter away from the reactor wall and ata height of about 5 to about 30 percent of the height of the bed.

A gas which is inert to the catalyst, such as nitrogen or argon, ispreferably used to carry the catalyst into the bed.

The rate of polymer production in the bed depends on the rate ofcatalyst injection and the concentration of monomer(s) in the reactionzone. The production rate is conveniently controlled by simply adjustingthe rate of catalyst injection.

Since any change in the rate of catalyst injection will change thereaction rate and thus the rate at which heat is generated in the bed;the temperature of the recycle stream entering the reactor is adjustedupwards and downwards to accommodate any change in the rate of heatgeneration. This ensures the maintenance of an essentially constanttemperature in the bed. Complete instrumentation of both the fluidizedbed and the recycle stream cooling system is, of course, useful todetect any temperature change in the bed so as to enable either theoperator or a conventional automatic control system to make a suitableadjustment in the temperature of the recycle stream.

Under a given set of operating conditions, the fluidized bed ismaintained at essentially a constant height by withdrawing a portion ofthe bed as product at the rate of formation of the particulate polymerproduct. Since the rate of heat generation is directly related to therate of product formation, a measurement of the temperature rise of thefluid across the reactor (the difference between inlet fluid temperatureand exit fluid temperature) is indicative of the rate of particularpolymer formation at a constant fluid velocity if no or negligiblevaporizable liquid is present in the inlet fluid.

On discharge of particulate polymer product from reactor 10, it isdesirable and preferable to separate fluid from the product and toreturn the fluid to the recycle line 22. There are numerous ways knownto the art to accomplish this. One preferred system is shown in thedrawings. Thus, fluid and product leave reactor 10 at point 44 and enterproduct discharge tank 46 through valve 48, which may be a ball valvewhich is designed to have minimum restriction to flow when opened.Positioned above and below product discharge tank 46 are conventionalvalves 50, 52 with the latter being adapted to provide passage ofproduct into product surge tank 54. Product surge tank 54 has ventingmeans illustrated by line 56 and gas entry means illustrated by line 58.Also positioned at the base of product surge tank 54, is a dischargevalve 60 which when in the open position discharges product forconveying to storage. Valve 50 when in the open position releases fluidto surge tank 62. Fluid from surge tank 62 is directed through a filterabsorber 64 and thence through a compressor 66 and into recycle line 22through line 68.

In a typical mode of operation, valve 48 is open and valves 50, 52 arein a closed position. Product and fluid enter product discharge tank 46.Valve 48 closes and the product is allowed to settle in productdischarge tank 46. Valve 50 is then opened permitting fluid to flow fromproduct discharge tank 46 to surge tank 62 from which it is continuallycompressed back into recycle line 22. Valve 50 is then closed and valve52 is opened and any product in product discharge tank 46 flows intoproduct surge tank 64. Valve 52 is then closed. The product is purgedwith inert gas, preferably nitrogen, which enters product surge tank 54through line 58 and is vented through line 56. Product is thendischarged from product surge tank 54 through valve 60 and conveyedthrough line 20 to storage.

The particular timing sequence of the valves is accomplished by the useof conventional programmable controllers which are well known in theart. Moreover, the valves can be kept substantially free of agglomeratedparticles by directing a stream of gas periodically through the valvesand back to the reactor.

Another preferred product discharge system which may be alternativelyemployed is that disclosed and claimed in U.S. Pat. No. 4,621,952. Sucha system employs at least one (parallel) pair of tanks comprising asettling tank and a transfer tank arranged in series and having theseparated gas phase returned from the top of the settling tank to apoint in the reactor near the top of the fluidized bed. Such alternativepreferred product discharge system obviates the need a recompressionline 64,66,68, as shown in the system of the drawing.

The fluidized-bed reactor is equipped with an adequate venting system(not shown) to allow venting the bed during start up and shut down. Thereactor does not require the use of stirring and/or wall scraping. Therecycle line 22 and the elements therein (compressor 30, heat exchanger24) should be smooth surfaced and devoid of unnecessary obstructions soas not to impede the flow of recycle fluid or entrained particles.

Conventional techniques for the prevention of fouling of the reactor andpolymer agglomeration can be used in the practice of our invention.illustrative of these techniques are the introduction of finely dividedparticulate matter to prevent agglomeration, as described in U.S. Pat.Nos. 4,994,534 and 5,200,477; the addition of negative charge generatingchemicals to balance positive voltages or the addition of positivecharge generating chemicals to neutralize negative voltage potentials asdescribed in U.S. Pat. No. 4,803,251. Antistat substances may also beadded, either continuously or intermittently to prevent or neutralizestatic charge generation. Condensing mode operation such as disclosed inU.S. Pat. Nos. 4,543,399 and 4,588,790 can also be used to ensureoperability of the fluid bed polymerization and to assist in heatremoval.

Illustrative of the polymers which can be produced in accordance withthe invention are the following:

Polyisoprene (cis-1, 4- Polyisoprene)

Polystyrene

Polybutadiene

SBR (polymer of butadiene copolymerized with styrene)

ABS (polymer of acrylonitrile, butadiene and styrene)

Nitrile (polymer of butadiene copolymerized with acrylonitrile)

Butyl (polymer of isobutylene copolymerized with isoprene)

EPR (polymer of ethylene copolymerized with propylene)

EPDM (polymer of ethylene copolymerized with propylene and a diene suchas hexadiene, dicyclopentadiene, or ethylidene norbornene)

Neoprene (polychloroprene)

Silicone (polydimethyl siloxane)

Copolymer of ethylene and vinyltrimethoxy silane

Copolymer of ethylene and one or more of acryonitrile, maleic acidesters, vinyl acetate, acrylic and methacrylic acid esters and the like

When it is desired to produce polymers or copolymers using one or moremonomers which are all relatively high boiling and which are liquidsunder the temperature and pressure conditions which are preferred forgas phase fluidized bed production in accordance with the invention, itis necessary to employ an inert substance which will remain gaseousunder the conditions selected for polymerization in the fluidized bed.Suitable for this purpose are inert gases such as nitrogen, argon, neon,krypton and the like. Also useful are saturated hydrocarbons such asethane, propane, butane and the like as well as halogen substitutedalkanes such as freon. Other materials which remain gaseous under thedesired conditions, such as carbon dioxide, provided they areessentially inert and do not affect catalyst performance, can also beemployed.

Nitrogen, because of its physical properties and relatively low cost isa preferred medium for the manufacture of polymers from higher boilingmononers such as styrene, vinyl acetic acid, acrylonitrile,methylacrylate, methylmethacrylate and the like. AIkanes such as ethaneand propane which remain gaseous at relatively low temperatures are alsopreferred.

Conventional techniques for the prevention of fouling of the reactor andpolymer agglomeration can be used in the practice of our invention.Illustrative of these techniques are the introduction of finely dividedparticulate matter to prevent agglomeration, as described in U.S. Pat.Nos. 4,994,534 and 5,200,477; addition of negative charge generatingchemicals to balance positive voltages or by addition of positive chargegenerating chemicals to neutralize negative voltage potentials asdescribed in U.S. Pat. No. 4,803,251. Antistat substances may also beadded, either continuously or intermittently to prevent or neutralizestatic charge generation.

The granular polybutadiene and/or polyisoprene elastomers of thisinvention can be compounded with other elastomers, e.g. natural rubber,styrene-butadiene rubber, (halo)butyl rubber, ethylene-propylene-dienerubber; reinforcing fillers, e.g. carbon black, silica; processing aids,antidegradants, and vulcanizing agents, using equipment and methods wellknown to those skilled in the art. In such compounds, the initiallygranular form of tile polybutadiene or polyisoprene may permit moreintimate mixing with the other elastomer(s), than would be achievablewith conventional polybutadiene or polyisoprene in solid bale form. Itis generally desirable that elastomer blends be intimately mixed inorder to optimize the mechanical properties of the vulcanizate.Furthermore, if the inert particulate material of this invention, usedto maintain granularity during and after the polymerization process,also happens to be a reinforcing filler for the compound (e.g., carbonblack), then a further benefit may be realized in the form of a shortermixing time required to disperse the filler in the compound. This isbecause the filler, which normally would have to first be deagglomeratedin the mixing process before it could be dispersed, in this case entersthe mixing process already substantially deagglomerated.

Elastomeric compounds prepared from granular polybutadiene and/orpolyisoprene, as described in the preceding paragraph, are particularlyuseful as components of pneumatic tires. For example, in the productionof a radial automobile tire, specially formulated elastomeric compoundscan be extruded through a die to produce strip stock for the tread,sidewall, and bead filler components of the tire, or to produce sheetstock for the air retention innerliner. Other specially formulatedelastomeric compounds can be calendered onto textile or steel cordfabric to produce cord-reinforced sheet stock for the carcass andcircumferential belt components of the tire. The “green” or unvulcanizedtire is built by assembling the various components (exceptcircumferential belt and tread) on the surface of a cylindrical drum,radially expanding and axially compressing the assembly to produce atoroidal shape, then placing the belt and tread components in positionaround the circumference of the toroid. Finally, the green tire isvulcanized by inflating with high pressure steam against the innersurface of a closed, heated aluminum mold. In the early stage of thevulcanization process, when the various elastomeric compounds are stillsoft and flowable, the pressure of the tire against the inner surface ofthe mold produces the final precise shape, tread pattern, sidewalllettering and decorative markings. Later in the vulcanization process,heat-activated crosslinking reactions take place within the variouselastomeric compounds, so that when the mold is finally opened, eachcompound has undergone crosslinking to a degree that is essentiallyoptimum for the intended service.

When used as a constituent of tire compounds, granular polybutadiene ofthis invention particularly imparts abrasion resistance, fatiguecracking resistance, low heat generation, and low rolling resistance.Granular polyisoprene of this invention particularly imparts buildingtack and green strength, which facilitate the building and handling ofthe green tire, and tear and cut resistance.

EXAMPLES

The following examples are provided to illustrate our invention.

Example 1

In an example of the process of the invention a fluidized bed reactionsystem as described above, is operated as described below to produceethylene-propylene diene terpolymer. The polymer is produced under thefollowing reaction conditions: 40° C. reactor temperature and 290 psiareactor pressure. The partial pressures (dew points) of the monomers andcomonomers inside the reactor are 90 psia for ethylene and 198 psia forpropylene. The partial pressure of hydrogen is 2.0 psia. The monomerethylidene-norbornene (ENB) is injected into the polymerization zone ofthe reactor at the rate of 0.53 lb/in. The volume of the reactor is 55ft3; the resin's weight inside the reactor was 112 lbs. The catalystsystem employed in this Example is vanadium acetyl acetonate withdiethylaluminum chloride as co-catalyst and ethyl trichloroacetate asthe promoter. The production rate is 20 lb/in. The product has a Mooneyvalue of 55.

About 75 percent of the injected ENB is incorporated into the polymersby polymerization. The unreacted remainder of ENB, dissolved intopolymers and is equal to 0.66 percent of the polymer's weight. With 112lbs. of resins inside the reactor, the total unreacted ENB is 0.74 lbs.If the unreacted ENB were completely evaporated inside the reactor, itspartial pressure would be 0.6764 psia.

At 40° C. the saturation pressure is 2187.7 psia for ethylene, 337.1psia for propylene and 0.262 psia for ENB. Since the partial pressuresof ethylene and propylene inside the reactor are much less than theirsaturation pressures, there is no condensed ethylene or propylene. Thecalculated partial pressure of unreacted ENB inside the reactor,however, is much higher than its saturation pressure. Therefore, the ENBmust be in a liquid state and been absorbed by the polymers.

Example 2

Ethylene-propylene diene terpolymer is made in a fluidized bed reactionsystem as described above under the following reaction conditions: 40°C. reactor temperature and 363.4 psia reactor pressure. The partialpressures of the monomers and comonomers inside the reactor are 90 psiafor ethylene and 198.2 psia for propylene. The partial pressure ofhydrogen is 2.2 psia, and the partial pressure of nitrogen was 72.6. Themonomer ethylidene norbornene (ENB) is injected into the polymerizationzone of the reactor at the rate of 0.53 lb/in. The volume of the reactoris 55 ft3; the resin's weight inside the reactor was 112 lbs. Thecatalyst system employed in this Example is vanadium acetyl acetonatewith diethylaluminum chloride as co-catalyst and ethyl trichloroacetateas the promoter. The production rate is 20 lb/in. The product has aMooney value of 55.

Seventy-five percent of the injected ENB is incorporated into polymersby polymerization. The unreacted remainder of ENB, dissolved intopolymers and is equal to 0.66 percent of the polymer's weight. With 112lbs. of resins inside the reactor, the total unreacted ENB is 0.74 lbs.If the unreacted ENB completely evaporates inside the reactor, itspartial pressure would be 0.6764 psia.

At 40° C. the saturation pressure is 2187.7 psia for ethylene, 337.1psia for propylene, and 0.262 psia, for ENB. Since the partial pressuresof ethylene and propylene inside the reactor are much less than theirsaturation pressures, there is no condensed ethylene or propylene. Thecalculated partial pressure of unreacted ENB inside the reactor,however, is much higher than its saturation pressure. Therefore, the ENBmust be in a liquid state and be absorbed by the polymers.

Examples 3 to 6

Examples 3 to 6 set forth in tabular form, operating conditions forproducing a variety of different polymers in accordance with theinvention. They illustrate the practice of the invention using differentcatalyst systems and differing cycle gas compositions.

EXAMPLE NO. 3 4 5 6 PRODUCT: POLYBUTADIENE SBR ABS POLYSTYRENE ReactionConditions: Temperature (° C.) 40 40 40 40 Pressure (psi) 100 110 200100 Superficial Velocity 1.75 2.0 1.5 1.5 (ft/s) Production Rate (lb/h)30 25 20 40 Total Reactor 55 55 55 55 Volume (ft3) Reaction Zone 7.5 7.57.5 7.5 Volume (ft3) Bed Height (ft) 7.0 7.0 7.0 7.0 Bed Diameter (ft)1.17 1.17 1.17 1.17 Bed Weight (lbs) 112 112 112 112 Cycle GasComposition: N2 20 27.3 58.0 99.7 Butadiene 80 72.5 39.9 — Styrene — .20.15 0.3 Acrylonitrile — — 1.95 — Catalyst: CO(acac)3* CO(acac)3*CO(acac)3* Cp2ZrMe2** Co-catalyst: Triethyl- Triethyl- Triethyl- MAO***aluminum aluminum aluminum Heavy Monomer Feed Rate (lb/h) Butadiene 46.29.62 2.46 — Styrene — 20.83 15.33 44.4 Acrylonitrile — 7.08 — PolymerComposition: Butadiene 100 25 8 — Styrene 75 69 100 Acrylonitrile — 23 —*Cobalt triacetylacetonate **Dicyclopentadienylzironiumdimethyl***Methylalumoxane

Examples 7 to 10 Example 7

A fluidized bed reaction system as described above, is operated asdescribed below to produce polybutadiene. The polymer is produced underthe following reaction conditions: 55° C. reactor temperature and 100psia total reactor pressure. The partial pressure of the butadienemonomer inside the reactor is 80 psia. The partial pressure of nitrogenis 20 psia. The catalyst system employed in this Example is cobalttris(acetylacetonate). It may be supported on silica or fed as asolution in methylene chloride. Methylaluminoxane is used asco-catalyst. Catalyst and co-catalyst feeds are adjusted to give a 400:1molar ratio of Al to Co. At steady state the monomer is fed into thereaction system at the rate of 47.8 lb/in. Dried N-650 carbon black isfed to the reactor at the rate of 20 lb/in. Butadiene monomer leaves thereactor at 15 lb/in in vent streams. The production rate is 30 lb/in ofpolymer after adjusting for the carbon black content. The product has aMooney viscosity ML (1+4@ 100° C.) of 55. Other conditions are shown forExample 7 in the table.

At steady state a total of 47.8 lb/in butadiene is being fed to thereactor and a total of 45 lb/in is accounted for leaving the reactor asgas in a vent stream or as polymer. The difference of 2.8 lb/in must beunreacted liquid butadiene monomer in the polymer leaving the reactor.Since the polymer discharged is identical with the polymer in the bed,the polymer in the bed must contain the same proportion of liquidmonomer, i.e. there must be 10.4 lbs of dissolved liquid monomer in the112 lbs polymer bed.

The reactor volume is 55 ft3. At the partial pressure of 80 psia, thereare 37.6 lbs of butadiene in the reactor gas-phase. The totalunpolymerized butadiene in the reactor is thus 48.0 lbs (=37.6+10.4). Ifall of this butadiene were in the gas phase of this reactor at once itwould have a partial pressure of 104 psia and its condensationtemperature would be 61° C. Therefore the reactor at 55° C. is beingoperated below the condensation temperature of the monomer present inthe polymerization zone. Furthermore, the presence of this liquidmonomer in the gas-phase reactor does not cause agglomeration of thepolymer.

EXAMPLE NO. 7 8 9 10 PRODUCT: POLYBUTADIENE SBR ABS POLYISOPRENEReaction Conditions: Temperature (° C.) 55 55 55 0 Total Pressure (psia)100 110 200 100 Superficial Velocity (ft/s) 1.75 2.0 1.5 1.75 ProductionRate (lb/h) 30 25 20 30 Total Reactor 55 55 55 55 Volume (ft3) ReactionZone 7.5 7.5 7.5 7.5 Volume (ft3) Bed Height (ft) 7.0 7.0 7.0 7.0 BedDiameter (ft) 1.17 1.17 1.17 1.17 Bed Weight (lbs) 112 112 112 112 CycleGas Composition (mole %): N2 20 27.3 58.0 70 Butadiene 80 72.5 39.9 —Styrene — 0.2 0.15 — Acrylonitrile — — 1.95 — Isoprene — — — 30Catalyst: CO(acac)3* CpTiCl3 CpTiCl3 TiCl4 Co-catalyst: MAO*** MAO***MAO*** TEAL** Monomer Feed Rate (lb/h) Butadiene 47.8 9.62 2.46 —Styrene — 20.83 15.33 — Acrylonitrile — — 7.08 — Isoprene — — — 35.4Total Monomer Vent 15 1 1 2 Rate (lb/h) Polymer Composition (wt. %):Butadiene 100 25 8 — Styrene — 75 69 — Acrylonitrile — — 23 — Isoprene —— — 100 *Cobalt triacetylacetonate **also Diphenyl Ether***Methylalumoxane

Examples 11 to 21 Example 11

To a gas-phase stirred bed reactor that is maintained at a constanttemperature of 22° C. 4.2 pounds of dried carbon black powder are addedto act as a fluidization aid. To this are added 0.039 lbs ethyl aluminumsesquichloride (EASC). Then is added 0.61 lb of 1,3-butadiene andsufficient nitrogen to bring the total reactor pressure to 315 psia. Asmall feed of supported CoC12(pyridine)4 catalyst is begun.Simultaneously, a small feed of 10 wt. % ethyl aluminum sesquichlorideco-catalyst solution in isopentane is begun. Feeds are adjusted to givea 15:1 molar ratio of Al:Co. During a 2.2 hour polymerization reaction,a total of 6.84 lbs of additional butadiene is fed in order to replacebutadiene that is polymerized or vented. A small vent stream leaving thereactor removes a total of 0.22 lbs butadiene during the polymerization.At the end of the polymerization, the catalyst and co-catalyst feeds arestopped. The reactor is Repressurized, and the reactor contents purgedfree of Residual butadiene using nitrogen. The polymer is dischargedfrom the reactor. The product does not contain any lumps that wouldindicate agglomeration had occurred. To the contrary, the product is afree-flowing, fine, granular powder. The reactor is opened and cleanedto ensure that all product is recovered. The total weight of solidproduct that is recovered is adjusted for the carbon black that has beeninitially charged. The remainder (5.73 lbs) is the amount of butadienepolymer formed during the batch and which is present in the reactor whenit is shut down. Since a total of 7.45 lbs (=6.84+0.61) of butadienewere charged to the reactor and a total of 5.95 lbs (=5.73+0.22) ofbutadiene have been accounted for leaving the reactor as polymer and inthe continuous vent stream, there must be 1.50 lbs of butadiene monomerpresent in the reactor when polymerization is terminated. This monomerwould be removed from the reactor when it is Repressurized and thecontents purged.

The reactor volume is 61.7 liters (or 2.18 cubic feet). At 22° C. thevapor pressure of 1,3-butadiene is 35 psia. The mass of butadienepresent in the reactor as a gas at saturation would thus be 0.73 lbs. Ofthe total of 1.50 lbs of unpolymerized butadiene that is shown to bepresent in the reactor at shutdown, at most 0.73 lbs could be in thevapor phase and the rest (0.77 lbs) must be present in a condensedphase, for example, dissolved in the polymer. Thus the reactor is beingoperated at a temperature below the condensation temperature of themonomer present. The 0.77 lbs of liquid monomer combined with the 5.73lbs of polymer amounts to 13.4 lbs of condensed butadiene monomer per100 lbs of polybutadiene. Yet, the presence of this liquid monomer inthe gas-phase reactor does not cause agglomeration of the polymer. Thetable provides a further summary of the example.

Examples 12 to 21 are conducted as in Example 11, but with the changesindicated in the table. Several particular changes are noted in furtherdetail below.

Supported Catalyst Preparation for Example 12

To a 500 mL dry nitrogen purged flask is added 31.9 grams of silica(600° C. activation) and 7.272 grams of CoC12 (pyridine)4. To this isadded 150 mL of CH2C12. The slurry is stirred for a few minutes and thenthe solvent was removed under vacuum.

Solution Catalyst Preparation for Example 18

Into a dry nitrogen purged flask is charged 1.648 grams of cobalt trisacetylacetonate. To this is added 100 mL of dry CH2C12. The mixture isstirred for a few minutes and charged to a pressurizable metal cylinderand fed to the reactor as a solution.

Example 14

To a gas-phase stirred bed reactor that is maintained at a constanttemperature of 20° C., 4.2 pounds of dried carbon black powder are addedto act as a fluidization aid. To this is added 0.045 lb methylaluminoxane (MAO). Then are added 1.01 lb of 1,3-butadiene andsufficient nitrogen to bring the total reactor pressure to 315 psia. Asmall feed of supported CoC12(pyridine)4 catalyst is begun.Simultaneously, a small feed of 10 wt. % MAO co-catalyst solution intoluene is begun. Feeds are adjusted to give a 607:1 molar ratio ofAl:Co. During a 1.33 hour polymerization reaction, a total of 6.50 lbsof additional butadiene are fed in order to replace butadiene that ispolymerized or vented. A total of 1.02 lbs of toluene are fed in theinitial and continuous feeds of MAO solution. A small vent streamleaving the reactor removes a total of 0.21 lbs butadiene and 0.005 lbstoluene during the polymerization. At the end of the polymerization, thecatalyst and co-catalyst feeds are stopped. The reactor isRepressurized, and the reactor contents purged free of residualbutadiene and toluene using nitrogen. The polymer is discharged from thereactor. The product does not contain any lumps that would indicateagglomeration has occurred. To the contrary, the product is afree-flowing, fine, granular powder. The reactor is opened and cleanedto ensure that all product is recovered. The total weight of solidproduct that is recovered is adjusted for the carbon black that has beeninitially charged. The remainder (5.81 lbs) is the amount of butadienepolymer formed during the batch and which is present in the reactor whenit is shut down. Since a total of 7.51 lbs (=6.50+1.01) of butadiene arecharged to the reactor and a total of 6.02 lbs (=5.81+0.21) of butadieneare accounted for leaving the reactor as polymer and in the continuousvent stream, there must be 1.49 lbs of butadiene monomer present in thereactor when polymerization is terminated. This monomer would be removedfrom the reactor when it is Repressurized and the contents purged.

The reactor volume is 61.7 liters (or 2.18 cubic feet). At 20° C. thevapor pressure of 1,3-butadiene is 35 psia. The mass of butadienepresent in the reactor as a gas at saturation would thus be 0.73 lbs. Ofthe total of 1.49 lbs of unpolymerized butadiene that is shown to bepresent in the reactor at shutdown, at most 0.73 lbs could be in thevapor phase and the rest (0.76 lbs) must be present in a condensedphase, for example, dissolved in the polymer. Thus the reactor is beingoperated at a temperature below the condensation temperature of themonomer present. The 0.76 lbs of liquid monomer combined with the 5.81lbs of polymer amounts to 13.1 lbs of condensed butadiene monomer per100 lbs of polybutadiene.

Similarly, since a total of 1.02 lbs of toluene are charged to thereactor and a total of 0.005 lbs of toluene are accounted for leavingthe reactor in the continuous vent stream, there must be 1.015 lbs oftoluene present in the reactor when polymerization is terminated. Thistoluene would be removed from the reactor when it is depressurized andthe contents purged. At 20° C. the vapor pressure of toluene is 0.46psia. The mass of toluene present in the reactor as a gas at saturationwould thus be 0.016 lbs. Of the total of 1.015 lbs of toluene that ispresent in the reactor at shutdown, at most 0.016 lbs could be in thevapor phase and the rest (1.0 lbs) must be present in a condensed phase,for example, dissolved in the polymer. Thus the reactor is operated at atemperature below the condensation temperature of the toluene present.The 1.0 lbs of liquid toluene combined with the 5.81 lbs of polymeramounts to 17.2 lbs of condensed butadiene monomer per 100 lbs ofpolybutadiene.

Thus, in this example there are a total of 30.3 lbs of condensedbutadiene and toluene per 100 lbs or polybutadiene in the gas-phasereactor, yet the presence of these liquid components does not causeagglomeration of the polymer. The table gives further details on thisexample.

EXAMPLE NO. 11 12 13 14 PRODUCT POLYBUTADIENE POLYBUTADIENEPOLYBUTADIENE POLYBUTADIENE CATALYST DETAILS Catalyst Cobalt CobaltCobalt acetyl Cobalt dichloride- dichloride- acetonate dichloride-pyndine pyridine on silica pyridine on silica on silica on silicaCo-catalyst 10% EASC in 15% DEACO in 10% EASC in 10% MAO isopentanetoluene isopentane toluene PROCESS CONDITIONS Reaction 22 23 20 20 Temp.(° C.) BD partial 30 30 30 30 pressure (psia) Polymer 5.7 6.3 5.4 5.8produced (lb) Reaction time 2 hr 10 min 3 hr 2 hr 15 min 1 hr 20 minPRODUCT ANALYSIS % Carbon Black 44 38 44 45 N-650 analysis Averageparticle 0.016 0.019 0.015 0.034 size by sieve analysis (inch)Aluminum/Catalyst 15 28 11 607 feed ratio* Cobalt content in 55 81 94 19the polymer (ppm) Reduced 1.5 1.0 1.0 3.6 Viscosity (dVg) Mooneyviscosity 42 ML (1 + 4 @ 100° C.) % cis-1,4 93 92 92 98.4 *molar ratioof Al to transition metal in continuous feeds

EXAMPLE NO. 15 16 17 18 PRODUCT POLYBUTADIENE POLYBUTADIENEPOLYBUTADIENE POLYBUTADIENE CATALYST DETAILS Catalyst Cobalt CobaltCobalt Cobalt acetyl dichloride dichloride octoate on acetonate inpyridine on pyridine- silica IPPDt chloride methylene diamine on diamineon silica silica Co-catalyst 10% MAO 15% EASC 15% 10% DEAC in in toluenetoluene DEACO isopentane in toluene PROCESS CONDITIONS Reaction Temp. (°C.) 20 20 20 20 BD partial 30 30 30 25 pressure (psia) Polymer produced(lb) 4.2 6.5 6.8 5.7 Reaction time 1 hr 4 hr 30 min 3 hr 10 min 4 hr 30min PRODUCT ALNALYSIS % Carbon Black 56 44 41 44 N-650 analysis Averageparticle 0.036 0.016 0.013 Size not size by sieve measured analysis(inch) A/V Catalyst feed 385 62 10 45 ratio* Cobalt content 45 84 195 45in the polymer (ppm) Reduced Viscosity 1.0 1.1 1.0 0.7 (dl/g) Mooneyviscosity 40 ML (1 + 4 @ 100° C.) % cis-1,4 95.7 96 92.1 90tN-phenyl-p-phenylenediamine was present on the catalyst at 15 moles permole of cobalt. *molar ratio of Al to transition metal in continuousfeeds

EXAMPLE NO. 19 20 21 PRODUCT POLYBUTADIENE POLYBUTADIENE POLYISOPRENECATALYST DETAILS Catalyst Cyclopentadiene Nickel octoate TiCl4/ titaniumdiphenyl-ether trichloride Co-catalyst 10% MAO in 10% TEAL TIBA toluene10% BF3 etherate PROCESS CONDITIONS Reaction 50 50 50 Temperature (° C.)Monomer partial 60 60 25 pressure (psia) Reaction time 2 hr 4 hr 4 hrPRODUCT ANALYSIS % Carbon Black 40 40 40 N-650 by analysisCo-catalyst/Catalyst 500 60 10 feed ratio* *molar ratio of Al totransition metal in continuous feeds

Examples 22 to 29 Example 22

To a gas-phase stirred bed reactor that is maintained at a constanttemperature of 60° C., 3.8 pounds of dried carbon black powder are addedto act as a fluidization aid. To this is added 0.055 lb TIBA, i.e.triisobutylaluminum. Then are added 1.86 lbs of 1,3-butadiene andsufficient nitrogen to bring the total reactor pressure to 315 psia. Asmall feed of supported catalyst consisting of neodymium neodecanoate onDEAC-treated silica is begun. Simultaneously, a small feed of 10 wt. %triisobutylaluminum co-catalyst solution in isopentane is begun. Feed isadjusted to give a 7:1 molar ratio of Al:Nd. During a 2.8 hourpolymerization reaction, a total of 6.93 lbs of additional butadiene arefed in order to replace butadiene that is polymerized or vented. A smallvent stream leaving the reactor removes a total of 0.95 lbs butadieneduring the polymerization. At the end of the polymerization, thecatalyst and co-catalyst feeds are stopped. The reactor isRepressurized, and the reactor contents purged free of residualbutadiene using nitrogen. The polymer is discharged from the reactor.The product does not contain any lumps that would indicate agglomerationhas occurred. To the contrary, the product is a free-flowing, fine,granular powder. The reactor is opened and cleaned to ensure that allproduct is recovered. The total weight of solid product that isrecovered is adjusted for the carbon black that has been initiallycharged. The remainder (5.35 lbs) is the amount of butadiene polymerformed during the batch and which is present in the reactor when it isshut down. Since a total of 8.79 lbs (=6.93+1.86) of butadiene arecharged to the reactor and a total of 6.30 lbs (=5.35+0.95) of butadieneare accounted for leaving the reactor as polymer and in the continuousvent stream, there must be 2.49 lbs of butadiene monomer present in thereactor when polymerization is terminated. This monomer would be removedfrom the reactor when it is Repressurized and the contents purged.

The reactor volume is 61.7 liters (or 2.18 cubic feet). At 60° C. thevapor pressure of 1,3-butadiene is 103 psia. The mass of butadienepresent in the reactor as a gas at saturation would thus be 1.88 lbs. Ofthe total of 2.49 lbs of unpolymerized butadiene that is present in thereactor at shutdown, at most 1.88 lbs could be in the vapor phase andthe rest (0.61 lbs) must be present in a condensed phase, for example,dissolved in the polymer. Thus the reactor is operated at a temperaturebelow the condensation temperature of the monomer present. The 0.61 lbof liquid monomer combined with the 5.35 lbs of polymer amounts to 11.4lbs of condensed butadiene monomer per 100 lbs of polybutadiene. Yet,the presence of this liquid monomer in the gas-phase reactor does notcause agglomeration of the polymer.

Examples 23 to 29 are conducted as in Example 22, but with the changesindicated in the tables.

Solution Catalyst Preparation for Example 23

Into a dry nitrogen purged flask is charged 12.32 grams of a hexanesolution of neodymium neodecanoate (5.4 wt. % Nd in hexane). To this areadded 85 mL dry hexane. To this solution are added 3.0 mL of 1.5 MEt2AlCl (1.Oeq AVNd). The mixture is stirred, charged to a pressurizablemetal cylinder and fed to the reactor as a solution.

Supported Catalyst Preparation for Example 24

To a 500 mL dry nitrogen purged flask are added 78.15 grams of silica(600° C. activation) and 250 mL dry hexane. Slowly, 40 mL of 1.5MEt2AlCl are added and the mixture is stirred for 60 minutes at roomtemperature. The solution is cooled and 117 grams of a hexane solutionof neodymium versatate (4.9 wt. % Nd) are added slowly. The mixture isstirred for 30 minutes and then the solvent is removed under vacuum.

EXAMPLE NO. 23 24 25 26 PRODUCT: POLYBUTADIENE POLYBUTADIENEPOLYBUTADIENE POLYBUTADIENE CATALYST DETAILS Catalyst NeodymiumNeodymium Neodymium Neodymium neodecanoate versatate on versatate onneodecanoate in hexane DEAC- DEAC-treated on DEAC- treated silica silicatreated silica Cocatalyst 10% TIBA in 10% TIBA in 1:3 10% DIBAHisopentane isopentane DIBAH: TIBA in isopentane in isopentane PROCESSCONDITIONS Reaction 50 60 60 60 Temperature (° C.) Monomer partial 63 6363 63 pressure (psia.) Polymer 6.8 5.8 6.4 4.5 produced (lb) Reactiontime 5 hr 2 hr 30 min 2 hr 15 min 3 hr PRODUCT ANALYSIS % Carbon Black42 41 41 42 N-650 by analysis Average particle 0.076 0.017 0.018 0.013size by sieve analysis (inch) Cocatalyst/Catalyst 21 7 9.5 11 Feedratio* Neodymium 132 288 179 415 content in the polymer (ppm) Reduced12.8 10.3 7.6 4.9 Viscosity (dl/g) Mooney viscosity 90 (est. gum) ML(1 + 4 @ 100° C.) % cis-1,4 99.1 97 96.2 97 *molar ratio of Al to rareearth metal in continuous feeds

EXAMPLE NO. 27 28 29 PRODUCT POLYBUTADIENE POLYBUTADIENE POLYISOPRENECATALYST DETAILS Catalyst Neodymium Neodymium Neodymium neodecanoate onneodecanoate on neodecanoate on DEAC-treated DEAC-treated DEAC-treatedsilica silica silica Cocatalyst 10% DIBAH in 10% DIBAH in 10% TIBA inisopentane isopentane isopentane PROCESS CONDITIONS Reaction 60 60 65Temperature (° C.) Monomer partial 63 63 35 pressure (psia) Polymer 5 4produced (lb) Reaction time 1 hr 45 min 1 hr 35 min 4 PRODUCT ANALYSIS %Carbon Black 36 39 40 N-650 by analysis Average particle 0.027 0.030size by sieve analysis (inch) Cocatalyst/Catalyst 28 29 Feed ratio*Neodymium 150 200 content in the polymer (ppm) Reduced Viscosity 4.2 3.7(dl/g) Mooney viscosity 62 39 (est. gum) ML (1 + 4 @ 100° C.) % cis-1,495.5 95.6 *molar ratio of Al to rare earth metal in continuous feeds

Example 30

In an example of the process of the invention a fluidized bed reactionsystem as described above, is operated as described below to producepolybutadienc. The polymer is produced under the following reactionconditions: 60° C. reactor temperature and 120 psia total reactorpressure. The partial pressure of the butadiene monomer inside thereactor is 96 psia. The partial pressure of nitrogen is 24 psia. Thecatalyst system employed in this Example is neodymium neodecanoatesupported on DEAC-treated silica with triisobutylaluminum asco-catalyst. Catalyst and co-catalyst feeds are adjusted to give a 60:1molar ratio of Al to Nd. At steady state the monomer is fed into thereaction system at the rate of 46.2 lb/in. Dried N-650 carbon black isfed to the reactor at the rate of 20 lb/in. Butadiene monomer leaves thereactor at 13 lb/in in vent streams. The production rate is 30 lb/in ofpolymer after adjusting for the carbon black content. The product has aMooney viscosity ML (1+4@ 100° C.) of 55. Other conditions are shown forExample 30 in the table.

At steady state a total of 46.2 lb/h butadiene is being fed to thereactor and a total of 43 Win is accounted for leaving the reactor asgas in a vent stream or as polymer. The difference of 3.2 lb/in must beunreacted liquid butadiene monomer in the polymer leaving the reactor.Since the polymer discharged is identical with the polymer in the bed,the polymer in the bed must contain the same proportion of liquidmonomer, i.e. there must be 11.9 lbs of dissolved liquid monomer in the112 lbs polymer bed.

The reactor volume is 55 ft At the partial pressure of 96 psia, thereare 44.4 lbs of butadiene in the reactor gas-phase. The totalunpolymerized butadiene in the reactor is thus 56.3 lbs (=44.4+11.9). Ifall of this butadiene were in the gas phase of this reactor at once itwould have a partial pressure of 125 psia and its condensationtemperature would be 69° C. Therefore the reactor at 60° C. is beingoperated below the condensation temperature of the monomer present inthe polymerization zone. Furthermore, the presence of this liquidmonomer in the gas-phase reactor does not cause agglomeration of thepolymer.

Example 31

In another example of the process of the invention the polymerization isconducted as described in Example 30 except that the catalyst isneodymium neodecanoate fed as a solution in hexane. The table givesfurther details on this example

Example 32

In an example of the process of the invention a fluidized bed reactionsystem as described above, is operated as described below to producepolyisoprene. The polymer is produced under the following reactionconditions: 65° C. reactor temperature and 100 psia total reactorpressure. The partial pressure of the isoprene monomer inside thereactor is 30 psia. The partial pressure of nitrogen is 70 psia. Thecatalyst system employed in this Example is neodymium neodecanoatesupported on DEAC-treated silica with triisobutylaluminum asco-catalyst. Catalyst and co-catalyst feeds are adjusted to give a 60:1molar ratio of Al to Nd. At steady state the monomer is fed into thereaction system at the rate of 35.4 lb/in. Dried N-650 carbon black isfed to the reactor at the rate of 20 lb/in. Isoprene monomer leaves thereactor at 2 lb/in in vent streams. The production rate is 30 lb/in ofpolymer after adjusting for the carbon black content. The product has aMooney viscosity ML (1+4@ 100° C.) of 55. Other conditions are shown forExample 32 in the table.

At steady state a total of 35.4 lb/in isoprene is being fed to thereactor and a total of 32 lb/in is accounted for leaving the reactor asgas in a vent stream or as polyiner. The difference of 3.4 lb/in must beunreacted liquid isoprene monomer in the polymer leaving the reactor.Since the polymer discharged is identical with the polymer in the bed,the polymer in the bed must contain the same proportion of liquidmonomer, i.e. there must be 12.7 lbs of dissolved liquid monomer in the112 lbg polymer bed.

The reactor volume is 55 ft3. At the partial pressure of 30 psia, thereare 17.2 lbs of isoprene in the reactor gas-phase. The totalunpolymerized isoprene in the reactor is thus 29.9 lbs (=17.2+12.7). Ifall of this isoprene were in the gas phase of this reactor at once itwould have a partial pressure of 54.5 psia and its condensationtemperature would be 80° C. Therefore the reactor at 65° C. is beingoperated below the condensation temperature of the monomer present inthe polymerization zone. Furthermore, the presence of this liquidmonomer in the gas-phase reactor does not cause agglomeration of thepolymer.

Example 33

In another example of the process of the invention the polymerization isconducted as described in Example 32 except that the catalyst isneodymium neodecanoate fed as a solution in hexane. The table givesfurther details on this example.

EXAMPLE NO. 30 31 32 33 PRODUCT: POLYBUTADIENE POLYBUTADIENEPOLYISOPRENE POLYISOPRENE Reaction Conditions: Temperature (° C.) 60 6065 65 Total Pressure 120 120 100 100 (psia) Superficial 1.75 1.75 1.751.75 Velocity (ft/s) Production Rate 30 30 30 30 (lb/h) Total Reactor 5555 55 55 Volume (ft3) Reaction Zone 7.5 7.5 7.5 7.5 Volume (ft3) BedHeight (ft) 7.0 7.0 7.0 7.0 Bed Diameter (ft) 1.17 1.17 1.17 1.17 BedWeight (lbs) 112 112 112 112 Cycle Gas Composition (mole %): N2 20 20 7070 Butadiene 80 80 — — Isoprene — — 30 30 Catalyst: Nd Nd Nd NdNeodecanoate Neodecanoate Neodecanoate Neodecanoate on DEAC- in hexaneon DEAC- in hexane treated silica treated silica Co-catalyst: TIBA TIBATIBA TIBA Monomer Feed Rate (lb/h) Butadiene 46.2 46.2 — — Isoprene — —35.4 35.4 Monomer Vent 13 13 2 2 Rate (lb/hr) Polymer Composition (wt.%): Butadiene 100 100 — — Isoprene — — 100 100

Example 34

In example 34, the fluid bed reactor of the type generally depicted inthe figure is employed. The reactor has a lower section about 3 metersin height and 0.36 meter in diameter and an upper section of about 4.5meters in height and 0.6 meter in diameter. In example 34, precursor isused to catalyze the reaction. The precursor is made by spray drying amagnesium chloride/titanium chloride/tetrahydrofuran solution with fumedsilica. The resulting solid is slurried with Kaydol mineral oil at aconcentration of approximately 28 weight percent solids. The precursoris introduced into the polymerization zone using both isopentane andnitrogen as a carrier. The superficial gas velocity is about 0.55 metersper second. Triethylaluminum in a 5% by weight solution of isopentane isalso added to the reactor. Mineral oil (Kaydol) is used as the liquidcomponent and is added to the recycle gases immediately prior to theirentry into the reaction vessel. The example is summarized below.

CATALYST: Titanium, wt. % of solids 2.47 THF, wt. % of solids 25Precursor Solids Concentration, wt % 28 REACTION CONDITIONS: ReactorTemp, ° C. 85 Reactor Pressure, psig 350 H2/C2 (mol) 0.009 C6/C2 (mol)0.035 C2 partial press., psi 33 iC5 conc., mole % 10 Residence time, hr.2.6 Catalyst feed rate (cc/hr) 8.5 Cocatalyst feed rate (cc/hr) 190Liquid Comp., wt. % in teed 9.05

Examples 35 to 37

In the following examples, a fluid bed reactor of the type generallydepicted in the figure is employed. The reactor has a lower sectionabout 3 meters in height and 0.33 meter in diameter and an upper sectionabout 4.8 meters in height and 0.6 meter in diameter. In each of theexamples, a catalyst is used which is obtained from a precursor made byimpregnating a magnesium chloride/titanium chloride/tetrahydrofurancomplex onto a triethylaluminum treated silica support. The silica isfirst dried at 600° C. to remove water and most of the surface silanols,and chemically treated with triethylaluminum to further passivate theremaining silanols. The dried, free-flowing precursor is then furtherreduced with diethylaluminum chloride in a tetrahydrofuran solution tobecome the finished catalyst. The catalyst is introduced into thepolymerization zone using a nitrogen carrier gas. The superficial gasVelocity is about 0.55 meters per second. Triethylaluminum in a 5% byweight solution of isopentane is also added to the reactor.

In example 35, silicone oil (L-45, 500 centistokes, available from OSiSpecialty Chemicals Inc., Danbury, Connecticut, United States ofAmerica) is used as the liquid component. In example 36, e-octane isused as the liquid component. In example 37, a solution of 35 weightpercent of a C16 alpha olefin mixture (about 75% cetene) in mineral oil(“Nujol”). The following table summarizes the experiments.

TABLE Example 35 36 37 Catalyst Composition: Titanium (wt. %) 1.22 1.081.15 DEAC/THF (mol) 0.6 0.2 0.4 TnHAl/THF (mol) 0 0.23 0.16 ReactionConditions Reactor Temp, ° C. 82 68 80 Reactor Pres. psia 315 315 315H2/C2 (mol) 0.253 0.218 0.202 C6/C2 (mol) 0.073 0.075 0.0 Liq. Comp.,wt. % in bed 10.23 12.53 9.27 C2 partial press. psia 38 35 32 N2 vol. %82 81.6 87 Residence time, hr. 3.2 3.8 3.4 Cocatalyst feed rate 135 135135 (cc/hr)

In each of the examples, fluidization is maintained and a free-flowingproduct is obtained. In example 37, cetene is incorporated into thepolyethylene polymer. In example 36, approximately a 500 millilitersample of polymer particles and reaction gases from the bed is withdrawnand the particles are allowed to settle without cooling in the presenceof ethylene at a pressure of about 315 psia. The sample exothermsslightly but the particles are not fused and octane is vaporized. Theincorporation of hexene in the copolymer of example 36 is slightlyhigher than that of a similar process but in which no octane is present.In each of the examples, the amount of fines in the product is reducedas compared to similar processes that do not employ the liquidcomponent. This confirms that Liquid Component in the polymerizationzone can affect polymer particle morphology.

Example 38

A bold model test is conducted to demonstrate the effect of free liquidin a fluidized bed. A gas fluidization system having a volume of 32cubic feet (907 liters) contains 55 pounds (25 Kg.) of the polymer ofexample 2. Nitrogen is circulated to achieve the fluidization and thetemperature is maintained at about 40° C. To the fluidized mixture isadded 9.3 pounds (4.2 Kg.) of octene. At 40° C., the amount of octenerequired to saturate the fluidization system is 0.34 pounds (155 g) andthe amount that could be sorbed by the polymer is about 6.1 pounds (2.75Kg). Microdroplets of octene circulated throughout the system. The testcontinued for 5 hours.

Examples 39 to 43

In these examples, a fluid bed reactor of the type generally depicted inthe figure is employed. The reactor has a lower section about 40.5 feet(about 12.3 meters) in height and 12.67 feet (about 3.9 meters) indiameter. A precursor is used to catalyze the reaction. The precursor ismade by spray drying a magnesium chloride/titaniumchloride/tetrahydrofuran solution with fumed silica and is similar tothat used in Example 35. The resulting solid is slurried with Kaydolmineral oil at a concentration of approximately 28 weight percentsolids. The precursor is introduced into the polymerization zone usingboth n-hexane and nitrogen as a carrier. The superficial gas velocity inthe reactor is about 0.63 meters per second. Triethylaluminum in a 5% byweight solution of n-hexane is also added to the reactor by injectioninto the recycle gas stream immediately prior to entry into the reactionvessel. Also, a feed of liquid n-hexane is provided to the recycle gasstream immediately prior to entry into the reactor. This stream is fedat ambient temperature. The amount of n-hexane fed is sufficient toreplenish that lost from the polymerization zone such as with dischargedpolyethylene such that the condensate weight percent in the gases to thereactor is substantially constant. The examples are summarized below.

Example 39* 40 41* 42 43 Product: Density (g/cc) 0.963 0.963 0.926 0.9260.926 Melt Index 8.2 8.2 49 48 52 Reaction Conditions: Temperature, ° C.108 108 89 88 87 Pressure, psig 350 350 350 350 350 C2 Pressure, psia178 175 108 111 110 Comonomer Butene Butene Butene C4/C2 0.32 0.32 0.32H2/C2 0.33 0.32 0.80 0.79 0.79 Catalyst Productivity, 4960 5630 29603220 3990 lbs product/lb catalyst Liquid Component n-hexane n-hexanen-hexane n-hexane n-hexane Reactor Inlet Temp., ° C. 64 85 49 65 65Cycle gas density, lb/ft3 1.23 1.78 1.38 1.64 1.74 Ethylene, mole % 4949 30 30 30 Nitrogen, mole % 15.4 10.6 22.9 20.8 19.1 Butene-1, mole %9.6 9.7 9.7 Hydrogen, mole % 16 16 24 24 24 Condensed liquid 0 21.5 017.9 23.9 in cycle gases at reactor inlet, wt. % Calculated dew −35 10822 89 95 point, ° C. Production rate, lbs/hr 30100 53600 31600 4700049700 *Comparative example

Examples 39 to 43 demonstrate the increased productivity of the reactoras the dew point is reached. Note in examples 42 and 43 that the dewpoint calculation exceeds the actual operating temperature. Inactuality, the dew point is the operating temperature of thepolymerization zone and the condensed hexane is in the liquid phase. Thehexane absorbed in the polymer does not enter into the dew pointcalculations. In examples 42 and 43, some carry over liquid hexane is inthe gases at the reactor outlet. Based upon mass balances around thereactor, in example 42, about 0.5 to 0.7 weight percent liquid iscontained in the gases leaving the reactor, and in example 43, about 5to 8 weight percent liquid are contained in the gases.

What is claimed:
 1. A method for the vapor phase polymerization of1,3-butadiene or isoprene monomer into a high cis-1,4polydiene whichcomprises the steps of charging said monomer and a suitable catalystinto a reaction zone within a gas fluidized bed reactor or a gas phasestirred reactor, the reaction zone containing an inert particulatematerial, and maintaining said monomer in the vapor phase in saidreaction zone by a suitable combination of temperature and pressure andwhere a portion of said monomer in tie reaction zone is in the liquidstate.
 2. A method according to claim 1 wherein the inert particulatematerial is finely divided carbon black particles.
 3. A method accordingto claim 1 wherein essentially no liquid is present in said reactionzone that is not adsorbed on or absorbed in solid particulate matter. 4.A method according to claim 1 wherein said catalyst is a rare earthbased catalyst.
 5. A method according to claim 1 wherein said catalystis a titanium based catalyst.
 6. A method according to claim 1 whereinsaid catalyst is a metallocene catalyst.
 7. A method according to claim1 wherein said catalyst is a neodymium based catalyst.
 8. A methodaccording to claim 1 wherein said catalyst is a neodymium alkanoatebased catalyst.
 9. A method according to claim 1 wherein saidpolymerization is conducted in the presence of an agent or device forregulating the level of static voltage in said reaction zone.
 10. Amethod for vapor phase polymerizing 1,3-butadiene into highcis-1,4-polybutadiene in a process comprising the steps of; (1) chargingsaid 1,3-butadiene and a catalyst comprising: (a) an organoaluminumcompound, (b) a soluble organonickel compound, and (c) hydrogen fluorideor a hydrogen fluoride complex into a reaction zone; wherein the1,3-butadiene is maintained in the vapor phase in said reaction zone bya suitable combination of temperature and pressure such that essentiallyno liquid is present in said reaction zone that is not adsorbed on orabsorbed in solid particulate matter; (2) allowing said 1,3-butadiene topolymerize into high cis-1,4-polybutadiene at a temperature within therange of about 20C to about 120C and (3) withdrawing said highcis-1,4-polybutadiene from said reaction zone.
 11. A method for vaporphase polymerizing isoprene into high cis-1,4-polyisoprene in a processcomprising the steps of: (1) charging said isoprene and a preformedcatalyst system which is made by reacting an organoaluminum compoundwith titanium tetrachloride in the presence of at least one ether;wherein the isoprene is maintained in the vapor phase in said reactionzone by a suitable combination of temperature and pressure and wherein aportion of said isoprene monomer in the reaction zone is in the liquidstate; (2) allowing said isoprene to polymerize into highcis-1,4-polyisoprene at a temperature within the range of about 20C toabout 120C and (3) withdrawing said high cis-1,4-polyisoprene from saidreaction zone.
 12. A method for vapor phase polymerizing isoprene intohigh cis-1,4-polyisoprene in a process comprising the steps of: (1)charging said isoprene and a catalyst comprising: (a) an organoaluminumcompound, (b) a soluble organonickel compound, and (c) hydrogen fluorideor a hydrogen fluoride complex into a reaction zone; wherein theisoprene is maintained in the vapor phase in said reaction zone by asuitable combination of temperature and pressure such that a portion ofthe monomer present in said reaction zone is a liquid that is notadsorbed on or absorbed in solid particulate matter; (2) allowing saidisoprene to polymerize into high cis-1,4-polyisoprene at a temperaturewithin the range of about 20C to about 120C and (3) withdrawing saidhigh cis-1,4-polyisoprene from said reaction zone.
 13. A method forvapor phase polymerizing isoprene into high cis-1,4-polyisoprene in aprocess comprising the steps of: (1) charging said isoprene and acatalyst comprising: (a) an organoaluminum compound, (b) a solubleorganonickel compound, and (c) hydrogen fluoride or a hydrogen fluoridecomplex into a reaction zone; wherein the isoprene is maintained in thevapor phase in said reaction zone by a suitable combination oftemperature and pressure such that essentially no liquid is present insaid reaction zone that is not adsorbed on or absorbed in solidparticulate matter and (2) allowing said isoprene to polymerize intohigh cis-1,4-polyisoprene at a temperature within the range of about 20Cto about 120C and (3) withdrawing said high cis-1,4-polyisoprene fromsaid reaction zone.